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Trường: THCS Văn Khê
Lớp : 8
Họ tên :............................
Điểm
KIểM TRA 15 phút-ĐạI Số
Lời phê
Bài 1:Cho các đa thức sau đã được phân tích thành nhân tử , hãy họn đáp án đúng(3điểm)
1/ 4x2-12x+9=
A. (2x+3)2
B.-(2x-3)2
C.(2x-3)2
D . (4x-3)2
2/ x3-6x2y+12xy2-8y3=
A.(x-y)3
B.x3-(2y)3
3/5x2-10x+10xy-20y=
A.5(x-2)(x+2y)
B.5(x-2)(x-2y)
C.(2x-y)3
C.5(x+2)(x+2y)
D.(x-2y)3
D.5(x+2)(x-2y)
Bài 2: Tìm biết:(6điểm)
a/ 3x(x-7)-x(7-x)=0
b/ x2- 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=
−5
− x + 2x − 2
2
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