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4x^2 - 5x + 9
= 4x^2 + 4x - 9x + 9
= 4x( x-1) -9(x-1)
= (4x-9)(x-1)
h nha
thanks
![](https://rs.olm.vn/images/avt/0.png?1311)
\(4x^2-5x-6=4x^2-8x+3x-6\)
\(=4x\left(x-2\right)+3\left(x-2\right)\)
\(=\left(x-2\right)\left(4x+3\right)\)
![](https://rs.olm.vn/images/avt/0.png?1311)
5x2 + 10xy - 4x - 8y
= 5x(x + 2y) - 2(x - 2y)
= (5x - 2)(x + 2y)
=(5x2 + 10xy) - (4x + 8y) = 5x.(x + 2y) - 4.(x + 2y) = (5x - 4).(x + 2y)
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#)Giải :
\(x^3-2x-4\)
\(=x^3+2x^2-2x^2+2x-4x-4\)
\(=x^3+2x^2+2x-2x^2-4x-4\)
\(=x\left(x^2+2x+2\right)-2\left(x^2+2x+2\right)\)
\(=\left(x-2\right)\left(x^2+2x+2\right)\)
\(x^4+2x^3+5x^2+4x-12\)
\(=x^4+x^3+6x^2+x^3+x^2+6x-2x^2-2x-12\)
\(=x^2\left(x^2+x+6\right)+x\left(x^2+x+6\right)-2\left(x^2+x+6\right)\)
\(=\left(x^2+x+6\right)\left(x^2+x-2\right)\)
\(=\left(x^2+x+6\right)\left(x-1\right)\left(x+2\right)\)
Câu 1.
Đoán được nghiệm là 2.Ta giải như sau:
\(x^3-2x-4\)
\(=x^3-2x^2+2x^2-4x+2x-4\)
\(=x^2\left(x-2\right)+2x\left(x-2\right)+2\left(x-2\right)\)
\(=\left(x-2\right)\left(x^2+2x+2\right)\)
![](https://rs.olm.vn/images/avt/0.png?1311)
b: \(=x\left(x^4-5x^2+4\right)\)
\(=x\left(x^4-x^2-4x^2+4\right)\)
\(=x\left(x^2-1\right)\left(x^2-4\right)\)
\(=x\left(x-1\right)\left(x+1\right)\left(x-2\right)\left(x+2\right)\)
a: Đa thức này không phân tích được bạn nhé
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a) Ta có: \(8x+4x^2-12xy\)
\(=4x\left(2+x-3y\right)\)
b) Ta có: \(5x^3-10x^2+5x\)
\(=5x\left(x^2-2x+1\right)\)
\(=5x\left(x-1\right)^2\)
c) Ta có: \(x^3+x^2y-xy^2-y^3\)
\(=x^2\left(x+y\right)-y^2\left(x+y\right)\)
\(=\left(x+y\right)\left(x^2-y^2\right)\)
\(=\left(x-y\right)\left(x+y\right)^2\)
d) Ta có: \(x^2-8x-9\)
\(=x^2-9x+x-9\)
\(=\left(x-9\right)\left(x+1\right)\)
a. `8x+4x^2-12xy=4x(2+x-3y)`
b) `5x^3-10x^2+5x=5x(x^2-2x+1)`
c) `x^3+x^2y-xy^2-y^3=x^2(x+y)-y^2(x+y)=(x+y)(x^2-y^2)=(x+y)^2 (x-y)`
d) `x^2-8x-9=(x^2-2.x.4+4^2)-25=(x-4)^2-5^2=(x+1)(x-9)`
![](https://rs.olm.vn/images/avt/0.png?1311)
\(4x\left(x+1\right)^2-5x^2\left(x+1\right)-4\left(x+1\right) =\left(x+1\right)\left[4x\left(x+1\right)-5x^2-4\right]=\left(x+1\right)\left(4x^2+4x-5x^2-4\right)=\left(x+1\right)\left(-x^2+4x-4\right)=-\left(x+1\right)\left(x-2\right)^2\)
\(4x\left(x+1\right)^2-5x^2\left(x+1\right)-4\left(x+1\right)\)
\(=4x\left(x^2+2x+1\right)-5x^2\left(x+1\right)-4\left(x+1\right)\)
\(=4x^3+8x^2+4x-5x^3-5x-4x-4\)
\(=-x^3+8x^2-5x-4\)
\(4x^2-5x-9\)
\(=4x^2+9x-4x-9\)
\(=x\left(4x+9\right)-\left(4x+9\right)\)
\(=\left(x-1\right)\left(4x+9\right)\)
Bài này phải học từ lớp 7 rồi chứ. Chúc bạn học tốt.
Xin lỡi, mình nhầm.
\(4x^2-5x-9\)
\(=4x^2-9x+4x-9\)
\(=x\left(4x-9\right)+4x-9\)
\(=\left(x+1\right)\left(4x-9\right)\)
Đây mới đúng.