Bài 2:
1: \(=x\left(x^2-1\right)=x\left(x-1\right)\left(x+1\right)\)
2: \(=x\left(y+z\right)-2\left(y+z\right)=\left(y+z\right)\left(x-2\right)\)
3:\(=x\left(x^4-5x^2+1\right)\)
\(=x\left(x^2-1\right)\left(x^2-4\right)=x\left(x-1\right)\left(x+1\right)\left(x-2\right)\left(x+2\right)\)