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(x+2)^2-9x^2
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`4x^3 - 4x^2 - 9x + 9`
`= (4x^3 - 4x^2) - (9x - 9)`
`= 4x^2(x - 1) - 9(x - 1)`
`= (4x^2 - 9)(x - 1)`
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`x^3 + 6x^2 + 11x + 6`
`= x^3 + x^2 + 5x^2 + 5x + 6x + 6`
`= (x^3 + x^2) + (5x^2 + 5x) + (6x + 6)`
`= x^2*(x + 1) + 5x(x + 1) + 6(x + 1)`
`= (x^2 + 5x + 6)(x+1)`
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`x^2y - x^3 - 9y + 9x`
`= (x^2y - 9y) - (x^3 - 9x)`
`= y(x^2 - 9) - x(x^2 - 9)`
`= (y - x)(x^2 - 9)`
b: =x^3+x^2+5x^2+5x+6x+6
=(x+1)(x^2+5x+6)
=(x+1)(x+2)(x+3)
c: =x^2(y-x)-9(y-x)
=(y-x)(x^2-9)
=(y-x)(x-3)(x+3)
a: =(4x^3-4x^2)-(9x-9)
=4x^2(x-1)-9(x-1)
=(x-1)(4x^2-9)
=(x-1)(2x-3)(2x+3)
\(\left(x^2-2.\frac{9x}{2}+\left(\frac{9}{2}\right)^2\right)+2-\frac{81}{4}\)
\(\left(x-\frac{9}{2}\right)^2-\frac{73}{4}=\left(x-\frac{9}{2}-\sqrt{\frac{73}{4}}\right)\left(x-\frac{9}{2}+\sqrt{\frac{73}{4}}\right)\)
P/S : h cho chua Pain
\(9x^2-4\left(x-1\right)^2\)
\(=\left[3x+2\left(x-1\right)\right]\left[3x-2\left(x-1\right)\right]\)
\(=\left[3x+2x-2\right]\left[3x-2x+2\right]\)
\(=\left(5x-2\right)\left(x+2\right)\)
\(=\left(x^2+2x\right)^2+9\left(x^2+2x\right)+20\)
\(=\left(x^2+2x+4\right)\left(x^2+2x+5\right)\)
\(x^3-9x^2+6x+16\\=x^3+x^2-10x^2-10x+16x+16\\=x^2(x+1)-10x(x+1)+16(x+1)\\=(x+1)(x^2-10x+16)\\=(x+1)(x^2-2x-8x+16)\\=(x+1)[x(x-2)-8(x-2)]\\=(x+1)(x-2)(x-8)\\Toru\)
\(\left(x^2+x\right)^2+9x^2+9x+14\)
= \(\left(x^2+x\right)^2-4+\left(9x^2+9x+18\right)\)
= \(\left(x^2+x\right)^2-2^2+9\left(x^2+x+2\right)\)
= \(\left(x^2+x+2\right)\left(x^2+x-2\right)+9\left(x^2+x+2\right)\)
= \(\left(x^2+x+2\right)\left(x^2+x+7\right)\)
Chúc bạn làm bài tốt!!!!!!
ai giúp mình với . ko bik có sai đề không chứ minh giải miết không ra
\(\left(x^2-3x+2\right)\left(x^2-9x+20\right)-40=\left(x-1\right)\left(x-2\right)\left(x-4\right)\left(x-5\right)-40\)
\(=\left(x^2-6x+5\right)\left(x^2-6x+8\right)-40\)
Đặt \(t=x^2-6x+5\) thì ta có \(t\left(t+3\right)-40=t^2+3t-40=\left(t+8\right)\left(t-5\right)\)
Suy ra \(\left(x^2-6x+5\right)\left(x^2-6x+8\right)-40=\left(x^2-6x+13\right)\left(x^2-6x\right)=x\left(x-6\right)\left(x^2-6x+13\right)\)
\(\left(x+2\right)^2-9x^2\)
\(=\left(x+2+3x\right)\left(x+2-3x\right)\)
\(=\left(4x+2\right)\left(-2x+2\right)\)
\(=-4\left(x-1\right)\left(2x+1\right)\)