Question

Giúp với ạ

Answer 1

1) \(x^3+6x^2y+12xy^2+8y^3=\left(x+2y\right)^3\)

2) \(3x^2-12y^2=3\left(x^2-4y^2\right)=3\left(x-2y\right)\left(x+2y\right)\)

3) \(x^2-y^2-x+y=\left(x-y\right)\left(x+y\right)-\left(x-y\right)\)

\(=\left(x-y\right)\left(x+y-1\right)\)

4) \(x^2-x-6=x\left(x-3\right)+2\left(x-3\right)=\left(x-3\right)\left(x+2\right)\)

5) \(x^3-19x-30=x^2\left(x-5\right)+5x\left(x-5\right)+6\left(x-5\right)\)

\(=\left(x-5\right)\left(x^2+5x+6\right)\)

\(=\left(x-5\right)\left[x\left(x+2\right)+3\left(x+2\right)\right]=\left(x-5\right)\left(x+2\right)\left(x+3\right)\)