Question

Phân tích thành nhân tử:

\(\text{a)}\)\(7x^2-28x+28\)

\(\text{b)}\)\(x^2-7x+12\)

\(\text{c)}x^3-2x+4\)

Answer 1

\(a,7x^2-28x+28\)

\(=7\left(x^2-4x+4\right)\)

\(=7\left(x^2-2x2+2^2\right)\)

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

Answer 2

b) \(x^2-7x+12=x^2-3x-4x+12=x\left(x-3\right)-4\left(x-3\right)=\left(x-3\right)\left(x-4\right)\)

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

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