Question

Answer 1

\(x^3-8-\left(x-2\right)\left(x-12\right)=0\)

\(\Leftrightarrow\left(x-2\right)\left(x^2+2x+4-x+12\right)=0\)

\(\Leftrightarrow x-2=0\)

hay x=2

Answer 2

\(\Rightarrow\left(x-2\right)\left(x^2+2x+4\right)-\left(x-2\right)\left(x-12\right)=0\)

\(\Rightarrow\left(x-2\right)\left(x^2+x+16\right)=0\)

\(\Rightarrow x=2\)(do \(x^2+x+16=\left(x+\dfrac{1}{2}\right)^2+\dfrac{63}{4}\ge\dfrac{63}{4}>0\))