giao an dai 8 chuong 2

Trờng: THCS Văn Khê
Lớp : 8
Họ tên :............................
KIểM TRA 15 phút-ĐạI Số
Điểm Lời phê
Bài 1:Cho các đa thức sau đã đợc phân tích thành nhân tử , hãy họn đáp án đúng(3điểm)
1/ 4x
2
-12x+9=
A. (2x+3)
2
B.-(2x-3)
2
C.(2x-3)
2
D . (4x-3)
2
2/ x
3
-6x
2
y+12xy
2
-8y
3
=
A.(x-y)
3
B.x
3
-(2y)

3
C.(2x-y)
3
D.(x-2y)
3
3/5x
2
-10x+10xy-20y=
A.5(x-2)(x+2y) B.5(x-2)(x-2y) C.5(x+2)(x+2y) D.5(x+2)(x-2y)
Bi 2 : Tìm biết:(6điểm)
a/ 3x(x-7)-x(7-x)=0 b/ x
2
- 6x+8=0
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c/ (2x-3)
2
=(x+5)
2
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Bài 3: Tìm max hoặc min nếu có của:(1điểm)
A=
2
5
2 2x x

+

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