Câu 1:
a: \(x^2\left(x-1\right)+4x\left(1-x\right)+4\left(x-1\right)\)
\(=x^2\left(x-1\right)-4x\left(x-1\right)+4\left(x-1\right)\)
\(=\left(x-1\right)\left(x^2-4x+4\right)=\left(x-1\right)\left(x-2\right)^2\)
b: \(4x^2-y^2+2y-1\)
\(=4x^2-\left(y^2-2y+1\right)\)
\(=\left(2x\right)^2-\left(y-1\right)^2\)
=(2x-y+1)(2x+y-1)
Câu 2:
a: \(\left(2x^3-3x^2-3x-1\right)\left(1-x\right)\)
\(=2x^3-2x^4-3x^2+3x^3-3x+3x^2-1+x\)
\(=-3x^4+5x^3-2x-1\)
b: \(\left(-x^4+6x^3-9x^2+8x-3\right):\left(x^2-5x+3\right)\)
\(=\left(-x^4+5x^3-3x^2+x^3-5x_{}^2+3x-x^2+5x-3\right):\left(x^2-5x+3\right)\)
\(=\frac{-x^2\left(x^2-5x+3\right)+x\left(x^2-5x+3\right)-\left(x^2-5x+3\right)}{x^2-5x+3}=-x^2+x-1\)
