KIEM TRA DAI 7 CHUONG 4

<span class='text_page_counter'>(1)</span>Trêng THCS L¹i Xu©n. Thø. ngµy. n¨m 2013. kiÓm tra 45’ M«n: §¹i sè. Líp : 7A Hä vµ tªn: ...................................................................................................... §iÓ m. th¸ng. TiÕt: 66 §Ò : 1. Lêi phª cña thÇy, c« gi¸o. .. Trắc nghiệm: (2đ) Khoanh tròn chữ cái A,(B, C, D) đứng trớc đáp án đúng. C©u 1: Gi¸ trÞ cña biÓu thøc 2x – 1 t¹i x = 2 lµ: A. 3; B.- 3; C. 5; D. -5 Câu 2: Trong các biểu thức sau, biểu thức nào không là đơn thức ? A. 3  x. 3 B. 4 ;. 2. 1 2 x yz B. 2 ;. D. 3x. 2. 2 Câu 3: Đơn thức 9x yz đồng dạng với đơn thức:. 1 2 xy z B. 2 ;. 2. . 1 2 x yz 3. A. 3xyz ; C. xyz ; D. Câu 4: Tổng của ba đơn thức 5xy2, 7xy2 và -15xy2 là: A. -3xy2 B. 27xy2; C. 3xy2; D.-3x2y C©u 5: Trong c¸c ®a thøc sau, ®a thøc nµo kh«ng ph¶i lµ ®a thøc mét biÕn ? 2. A. x  2 xy  y. 2. 2 C. y  0, 2 y  0, 25. 1 x3  x 2  x  1 2 B. 2 2 D. x  2ax  a (a lµ h»ng sè). 5 3 5 6 5 8 C©u 6: Cho ®a thøc A = x  3x y  y x  2 x y  x a) Bậc của đa thức đối với biến x là: A. 8; B. 5; C. 3; b) Bậc của đa thức đối với biến y là: A. 6; B. 5; C. 1; C©u 7: x = 3 lµ nghiÖm cña ®a thøc: A. x + 3; B. 3x - 27; C. 3x + 27;. D. Mét sè kh¸c D. Mét sè kh¸c D. 3x2 - 27. Tù luËn: 2 3 2 x y z (3 x 2 yz ) 2 3 Câu 1(2 đ): a) Thu gọn đơn thức, tìm bậc và hệ số của đơn thức A =. b) TÝnh tæng: 3a2b - a2b + 2a2b + 5a2b. .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... ..

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C©u 2(2,5®):. a) T×m ®a thøc M, biÕt: M + (x2y - 2xy2 + xy + 1) = x2y + xy2 - xy - 1 b) TÝnh gi¸ trÞ cña ®a thøc M, biÕt x = 1; y = 2. .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... .. C©u 3(3 ®): Cho c¸c ®a thøc: f(x) = -3 + 5x + x3 + 3x4 g(x) = - x3 + x2 - 5x + 2 - 3x4 a. TÝnh f(x) + g(x); f(x) - g(x) b. T×m nghiÖm cña ®a thøc f(x) + g(x) .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... ..

<span class='text_page_counter'>(3)</span> .......................................................................................................................................................................................................................................................................................................................... .. Câu 4: Cho 2 đa thức A(x) = 3.x 2 - 2b.x + 5 và B(x) = a.x 2 + 6.x + c. Xác định các số a, b, c để A(x) = B(x) .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... .. Trêng THCS L¹i Xu©n. Thø. ngµy. th¸ng. n¨m 2013. kiÓm tra 45’ M«n: §¹i sè. Líp : 7A Hä vµ tªn: ................................................................................................... §iÓ m. TiÕt: 66 §Ò : 2. Lêi phª cña thÇy, c« gi¸o. .. BàI 1: (2đ) Khoanh tròn chữ cái A,(B, C, D) đứng trớc đáp án đúng. C©u 1: Gi¸ trÞ cña biÓu thøc 2x + 1 t¹i x = 2 lµ: A. 3; B. - 3; C. 5; D. -5 Câu 2: Trong các biểu thức sau, biểu thức nào không là đơn thức ? 3 2 2 x y ( 3 xy 5 ) B. 5 ;. A. 1  xy ; Câu 3: Đơn thức 2x3y2 đồng dạng với đơn thức: 2 3. A. -2x y. B. (xy). 3. C.. 1 x2 y . C. 2 a. . 1 2 3 y x 3. 2 3 D. ( 5 x y ) z. D. -2x2y2. Câu 4: Tổng của ba đơn thức 2xy3; 5xy3 và -7x3y là: B. 7xy3-7x3y. A. 0 C©u 5: Cho tÝch sau. (-2xy3) . (. a, Tích của hai đơn thức trên là; A: −. 2 3 5 xy 3. B: −. C. 14x3y. 1 xy ) 3. 2 2 4 xy 3. C: −. b, Bậc của đơn thức tích trên là: A: BËc8 B: BËc 6 5. 3. 5. 2 3 5 xy 9. C; BËc 5 6. 5. D: −. 2 2 4 xy 9. D: BËc 4.. 8. C©u 6: Cho ®a thøc A = x  3x y  y x  2 x y  x a) Bậc của đa thức A đối với tất cả các biến là: A. 8; B. 6; C. 7; b) Bậc của đa thức A đối với biến y là: A. 6; B. 5; C. 1; BµI 2:. D. 7x2y6-7x3y. D. 5 D. Mét sè kh¸c.

<span class='text_page_counter'>(4)</span> C©u 1(2®): đó.. a) Thu gọn đơn thức A =. 1 2 3 x yz . ( − 3 xy )2 rồi tìm bậc và hệ số của đơn thức 3. b) TÝnh tæng: 3ab2c - ab2c + 6ab2c + ab2c. .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... .. C©u 2(2,5®): a) T×m ®a thøc M, biÕt: (x2y - 2xy2 + xy + 1) - M = x2y + xy2 - xy - 1 b) TÝnh gi¸ trÞ cña ®a thøc M, biÕt x = 1; y = 2 .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... .. C©u 3(3 ®): Cho c¸c ®a thøc: f(x) = 15x3 + 7x2 + 3x -. g(x) = - 15x3 - 7x2 - 3x +. 1 2. 1 2. + 3x4. + 2x4. a. TÝnh f(x) + g(x); f(x) - g(x) b. Tìm nghiệm của đa thức tổng f(x) + g(x) vừa tìm đợc .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... . .......................................................................................................................................................................................................................................................................................................................... ..

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