phân tích đa thức thành nhân tử dạng đặt biến phụ
1, (x^2-x+2)^4-3x^2(x^2-x+2)^2+2x^4
2, 3(-x^2+2x+3)^4-26x^2(-x^2+2x+3)^2-9x^4
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\(x^2+2xy+y^2+2x+2y-15\)
\(=\left(x+y\right)^2+2\left(x+y\right)+1-16\)
\(=\left(x+y+1\right)^2-4^2=\left(x+y-3\right)\left(x+y+5\right)\)
\(x^2+2xy+y^2+2x+2y-15\)
\(=x^2+2xy+y^2+2x+2y+1-16\)
\(=\left(x+y\right)^2+2\left(x+y\right)+1-16\)
Đặt \(x+y=t\)
\(\Rightarrow t^2+2t+1-16\)
\(=\left(t+1\right)^2-4^2\)
\(=\left(t+1-4\right)\left(t+1+4\right)\)
\(=\left(t-3\right)\left(t+5\right)\)
\(=\left(x+y-3\right)\left(x+y+5\right)\)
phân tích đa thức thành nhân tử 4x^3+6x^2+4x+1
= 4x^3+6x^2+4x+1
= (2x+1)(2x^2+2x+1)
nha bạn chúc bạn học tốt nha
\(4x^3+6x^2+4x+1\)
\(=4x^3+4x^2+2x^2+2x+2x+1\)
\(=\left(4x^3+4x^2+2x\right)+\left(2x^2+2x+1\right)\)
\(=2x\left(2x^2+2x+1\right)+\left(2x^2+2x+1\right)\)
\(=\left(2x^2+2x+1\right)\left(2x+1\right)\)
phân tích đa thức thành nhân tử 6x^3+x^2+x+1
= 6x^3+x^2+x+1
= (2x+1)(3x^2-x+1)
chúc bạn học tốt nha
\(x^3+3x^2-10x-24\)
\(=x^3-3x^2+6x^2-18x+8x-24\)
\(=x^2\left(x-3\right)+6x\left(x-3\right)-8\left(x-3\right)\)
\(=\left(x-3\right)\left(x^2+6x-8\right)\)
\(=\left(x-3\right)\left(x^2+6x+9-1\right)\)
\(=\left(x-3\right)[\left(x-3\right)^2-1]\)
\(=\left(x-3\right)\left(x+2\right)\left(x+4\right)\)
\(2x^3-11x^2+10x+8\)
\(=2x^3-4x^2-7x^2+14x-4x+8\)
\(=2x^2\left(x-2\right)-7x\left(x-2\right)-4\left(x-2\right)\)
\(=\left(x-2\right)\left(2x^2-7x-4\right)\)
\(=\left(x-2\right)[2x\left(x-4\right)+\left(x-4\right)]\)
\(=\left(x-2\right)\left(x-4\right)\left(2x+1\right)\)
Ta có: \(^{3x^3-4x^2+13x-4}\) = \(3x^3-x^2-3x^2+x+12x-4\)
= \(3x^2\left(x-\frac{1}{3}\right)-3x\left(x-\frac{1}{3}\right)+12\left(x-\frac{1}{3}\right)\)
= \(\left(3x^2-3x+12\right)\left(x-\frac{1}{3}\right)\)
= \(3\left(x^2-x+4\right)\left(x-\frac{1}{3}\right)\)
3x^3-4x^2+13x-4
= (3x-1)(x^2-x+4)
nha bạn
\(2x^3-35x+75=2x^3+10x^2-10x^2-50x+15x+75\)
\(=\left(x+5\right)\left[2x^2-10x+15\right]\)
\(1,2x^3+3x^2-8x+3\)
\(=2x^3-2x^2+5x^2-5x-3x+3\)
\(=2x^2\left(x-1\right)+5x\left(x-1\right)-3\left(x-1\right)\)
\(=\left(2x^2+5x-3\right)\left(x-1\right)\)
\(=\left(2x-1\right)\left(x+3\right)\left(x-1\right)\)
\(2,x^3-5x^2+2x+8\)
\(=x^3+x^2-6x^2-6x+8x+8\)
\(=x^2\left(x+1\right)-6x\left(x+1\right)+8\left(x+1\right)\)
\(=\left(x^2-6x+8\right)\left(x+1\right)\)
\(=\left(x-2\right)\left(x-4\right)\left(x+1\right)\)
\(3,-6x^3+x^2+5x-2\)
\(=-6x^3-6x^2+7x^2+7x-2x-2\)
\(=-6x^2\left(x+1\right)+7x\left(x+1\right)-2\left(x+1\right)\)
\(=\left(-6x^2+7x-2\right)\left(x+1\right)\)
\(=\left(-6x^2-3x-4x-2\right)\left(x+1\right)\)
\(=\left[-3x\left(2x+1\right)-2\left(2x+1\right)\right]\left(x+1\right)\)
\(=\left(-3x-2\right)\left(2x+1\right)\left(x+1\right)\)
\(4,3x^3+19x^2+4x-12\)
\(=3x^3+18x^2+x^2+6x-2x-12\)
\(=3x^2\left(x+6\right)+x\left(x+6\right)-2\left(x+6\right)\)
\(=\left(3x^2+x-2\right)\left(x+6\right)\)
\(=\left(3x-2\right)\left(x+1\right)\left(x+6\right)\)
\(1,\)
\(\left(x^2-x+2\right)^4-3x^2\left(x^2-x+2\right)^2+2x^4\)
Đặt: \(\left(x^2-x+2\right)^2=n\)
\(\left(x^2-x+2\right)^4-3x^2\left(x^2-x+2\right)^2+2x^4\)
\(=n^2-3x^2n+2x^4\)
\(=n\left(n-2x^2\right)-x^2\left(n-2x^2\right)\)
\(=\left(n-2x^2\right)\left(n-x^2\right)\)
Thay \(\left(x^2-x+2\right)^2\)ta có:
\(=[\left(x^2-x+2\right)^2-2x^2][\left(x^2-x+2\right)^2-x^2]\)
\(=[\left(x^2-x+2\right)^2-2x^2]\left(x^2-x+2-x\right)\left(x^2-x+2+x\right)\)
\(=[\left(x^2-x+2\right)^2-2x^2]\left(x^2-2x+2\right)\left(x^2+2\right)\)
\(2,\)
\(3\left(-x^2+2x+3\right)^4-26x^2\left(-x^2+2x+3\right)^2-9x^4\)
\(=3\left(-x^2+2x+3\right)^4+x^2\left(-x^2+2x+3\right)^2-27x^2\left(-x^2+2x+3\right)^2-9x^4\)
\(=\left(-x^2+2x+3\right)^2[3\left(-x^2+2x+3\right)^2+x^2]-9x^2[\left(-x^2+2x+3\right)^2+x^2]\)
\(=[3\left(-x^2+2x+3\right)^2+x^2][\left(-x^2+2x+3\right)^2-9x^2]\)