Question

Giúp mình 3 câu này với

a) x⁴ + x³ - 8x - 8

b) xy + 2y - 3(x + 2)

c) 3(x - y) + ay - ax

Answer 1

a) \(x^4+x^3-8x-8\)

\(=x^3\left(x+1\right)-8\left(x+1\right)\)

\(=\left(x^3+8\right)\left(x+1\right)\)

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

Answer 2

a) \(=x^3\left(x+1\right)-8\left(x+1\right)=\left(x+1\right)\left(x^3-8\right)=\left(x+1\right)\left(x-2\right)\left(x^2+2x+4\right)\)

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

c) \(=3\left(x-y\right)-a\left(x-y\right)=\left(x-y\right)\left(3-a\right)\)

Answer 3

b) \(xy+2y-3\left(x+2\right)\)

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

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

c) \(3\left(x-y\right)+ay-ax\)

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

\(=3\left(x-y\right)-a\left(x-y\right)\)

\(=\left(3-a\right)\left(x-y\right)\)