Question

tìm x bt : x(x-2)(x+2)-(x+2)(x^2-2x+4)=4

Answer 1

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

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

\(\Rightarrow x^3-4x-x^3-8=4\)

\(\Rightarrow4x=-12\Rightarrow x=-3\)

Answer 2

\(\Leftrightarrow x^3-4x-x^3-8=4\)

\(\Leftrightarrow-4x=12\)

hay x=-3