b)2x^2+xy-y^2=x^2+xy +x^2-y^2=x(x+y) +(x-y)(x+y) =(x+y)(x+x-y)=(x+y)(2x-y)
a)x^3-2x^2-x+2=x^2(x-2)-(x-2)=(x^2-1)(x-2)=(x-1)(x+1)(x-2)
a. \(x^3-2x^2-x+2=x^2\left(x-2\right)-\left(x-2\right)=\left(x-2\right)\left(x^2-1\right)=\left(x-2\right)\left(x-1\right)\left(x+1\right)\)
b. \(2x^2+xy-y^2=2x^2+2xy-xy-y^2=2x\left(x+y\right)-y\left(x+y\right)=\left(x+y\right)\left(2x-y\right)\)
Câu a :
\(x^3-2x^2-x+2\)
\(=x^2\left(x-2\right)-\left(x-2\right)\)
\(=\left(x-2\right)\left(x^2-1\right)\)
\(=\left(x-2\right)\left(x-1\right)\left(x+1\right)\)
Câu b :
\(2x^2+xy-y^2\)
\(=\left(x^2+xy\right)+\left(x^2-y^2\right)\)
\(=x\left(x+y\right)+\left(x-y\right)\left(x+y\right)\)
\(=\left(x+y\right)\left(2x-y\right)\)
Câu c :
\(x^3-6x^2+16\)
\(=x^3-2x^2-4x^2+8x-8x+16\)
\(=x^2\left(x-2\right)-4x\left(x-2\right)-8\left(x-2\right)\)
\(=\left(x-2\right)\left(x^2-4x-8\right)\)
Wish you study well !!