Question

Giúp mk vs ạ, mk cảm tạ ạ.

Answer 1

a) \(9-x^2\)

\(=3^2-x^2\)

\(=\left(3-x\right)\left(3+x\right)\)

b) \(x^2-y^2+14x+49\)

\(=\left(x^2+14x+49\right)-y^2\)

\(=\left(x+7\right)^2-y^2\)

\(=\left(x+y+7\right)\left(x-y+7\right)\)

Answer 2

c) \(x\left(2-x\right)-x+2\)

\(=x\left(2-x\right)-\left(x-2\right)\)

\(=x\left(2-x\right)+\left(2-x\right)\)

\(=\left(x+1\right)\left(2-x\right)\)

d) \(x^2\left(x-1\right)-4x^2+8x-4\)

\(=x^2\left(x-1\right)-\left(4x^2-8x+4\right)\)

\(=x^2\left(x-1\right)-4\left(x^2-2x+1\right)\)

\(=x^2\left(x-1\right)-\left(4x-4\right)\left(x-1\right)\)

\(=\left(x^2-4x-4\right)\left(x-1\right)\)