Question

phân tích :

a, A = ( x^2 + 4x + 8 )^2 + 3x ( x^2 +4x +8 ) + 2x^2

Answer 1

Đặt \(x^2+4x+8\) =a

\(\Rightarrow A=a^2+3x.a+2x^2\)

\(\Rightarrow A=a^2-xa-2xa+2x^2\)

\(\Rightarrow A=a\left(a-x\right)-2x\left(a-x\right)\)

\(\Rightarrow A=\left(a-x\right)\left(a-2x\right)\)