Question

(x-3)(2x+6)+6=6

Answer 1

\(\left(x-3\right)\left(2x+6\right)+6=6\)

\(\left(x-3\right)\left(2x+6\right)=0\)

\(\left(x-3\right)\left(x+3\right)=0\)

\(x^2-9=0\)

\(x^2=9\)

⇒ \(\left[{}\begin{matrix}x=3\\x=-3\end{matrix}\right.\)

Answer 2

\(\Leftrightarrow2x^2+6x-6x-18+6=6\)

\(\Leftrightarrow\left(x-3\right)\left(x+3\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=3\\x=-3\end{matrix}\right.\)