Kiểm tra chương I môn: Đại số 8 - Trường THCS Lê Quý Đôn

<span class='text_page_counter'>(1)</span>TRƯỜNG THCS LÊ QUÝ ĐÔN LỚP: 8 HỌ VÀ TÊN :……………………………………… Điểm. KIỂM TRA CHƯƠNG I MÔN : ĐẠI SỐ 8 (NH: 2009-2010) THỜI GIAN: 45 PHÚT. Lời phê của giáo viên. I/ TRẮC NGHIỆM: (4 điểm) Học sinh đánh dấu chéo ( X ) vào câu trả lời đúng 1/ 2x3.(3x2 – x) = ? A/ 6x6 – x B/ 6x5 – x C/ 6x5 – 2x3 2/ (x + 3)2 = ? A/ x2 + 3x + 9 B/ x2 + 3x + 6 C/ x2 + 6x + 9 3/ (2x – 3)2 = ? A/ 2x2 – 12x + 6 B/ 2x2 – 12x + 9 C/ 4x2 – 12x + 6 4/ (5x – 2)(5x + 2) = ? A/ 5x2 – 4 B/ 5x2 + 4 C/ 25x2 – 4 5/ Phân tích x(x – 2) + 4 – 2x thành nhân tử ta được: A/ (x – 2)2 B/ (x – 2)(x + 2) C/ (x – 2)(x + 4) 6/ (12x3y4 – 4x3y2) : ( - 4x3y2) = ? A/ - 3y2 B/ - 3y2 + 1 C/ 3y2 7/ Giá trị của biểu thức : x3 – 3x2 + 3x – 1 tại x = 21 là : A. 0 B. 60 C. 80 D. 8000 8/ Tìm x biết : ( 2x – 3 ) . ( x – 2 ) = 0 ta được : 3 2. A. x  ; x  2. B. x . 3 ;x  2 2. 3 2. C. x  ; x  2. II/ TỰ LUẬN: (6 điểm) 1/ Phân tích đa thức thành nhân tử: a/ x 3  6 x 2  9 x b/ x2 – 2xy + 3x – 6y c/ x2 – 9 – (x + 3)2 d/ x3 + 4x2 + 4x – 16xy2 2/ Làm tính chia: (2x4 – 3x3 + 3x2 – 3x + 1) : (x2 + 1) 3/ Tìm x, biết : x3 – 10x2 + 25x = 0. D/ 6x5 – 2x4 D/ x2 + 6x + 6 D/ 4x2 – 12x + 9 D/ 25x2 + 4 D/ Kết quả khác D/ 3y2 – 1. D. x = 0 (4 điểm). (1 điểm) (1 điểm). Bài làm .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. Lop8.net.

<span class='text_page_counter'>(2)</span> .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. .............................................................................................................................................................. Lop8.net.

<span class='text_page_counter'>(3)</span> TRƯỜNG THCS LÊ QUÝ ĐÔN – BẾN CÁT HƯỚNG DẪN CHẤM KIỂM TRA CHƯƠNG I ĐẠI SỐ 8 NĂM HỌC: 2009 - 2010 Giáo viên: Nguyễn Văn Thuận I/ TRẮC NGHIỆM (4 điểm) Mỗi câu đúng cho 0,5 điểm 1/ D 2/ C 3/ D 4/ C 5/ A 6/ B 7/ D 8/ A II/ TỰ LUẬN ( 6 điểm ): 1/ Phân tích đa thức thành nhân tử (4 điểm) a/ x 3  6 x 2  9 x = x (x2 – 6x + 9) = x(x – 3)2 b/ x2 – 2xy + 3x – 6y = x(x – 2y) +3(x – 2y) = (x – 2y)(x + 3) c/ x2 – 9 – (x + 3)2 = (x + 3)(x – 3) – (x + 3)2 = (x + 3)[(x – 3) – (x + 3)] = -6(x + 3) d/ x3 + 4x2 + 4x – 16xy2 = x[(x + 2)2 – (4y)2] = x(x+2+4y)(x +2 – 4y) 2/ (2x4 – 3x3 + 3x2 – 3x + a) : (x2 + 1) 2x4 – 3x3 + 3x2 – 3x + 1 + 2x2 - 3x3 + x2 – 3x + 1 – - 3x3 – 3x 2 x +1 – 2 x +1 0. – 2x4. x2 + 1 2x2 – 3x +1. (1 đ). 3/ Tìm x, biết :(1 điểm) x3-10x2+25x = 0 x(x2-10x+25) = 0 x(x2-2.x.5+52) =0 x(x-5) = 0 Suy ra x = 0 hoặc x = 5. Lop8.net. (0.25 điểm) (0.25 điểm) (0.5 điểm). (1 đ) (1 đ) (1 đ) (1 đ).

<span class='text_page_counter'>(4)</span>