Question

(x-1)(x+2)-x-2=0

Answer 1

\(\left(x-1\right)\left(x+2\right)-x-2=0\)

\(\Leftrightarrow\left(x-1\right)\left(x+2\right)-\left(x+2\right)=0\)

\(\Leftrightarrow\left(x+2\right)\left(x-2\right)=0\Leftrightarrow x=\pm2\)

Answer 2

\(\left(x-1\right)\left(x+2\right)-x-2=0\)

\(\Leftrightarrow\left(x-1\right)\left(x+2\right)-\left(x+2\right)=0\)

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

\(\Leftrightarrow\left[{}\begin{matrix}x-2=0\\x+2=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=2\\x=-2\end{matrix}\right.\)

Answer 3

\(\left(x-1\right)\left(x+2\right)-x-2=0\)

\(\Rightarrow\left(x-1\right)\left(x+2\right)-\left(x+2\right)=0\)

\(\Rightarrow\left(x+2\right)\left(x-1-1\right)=0\)

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

\(\Rightarrow\left[{}\begin{matrix}x+2=0\\x-2=0\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=-2\\x=2\end{matrix}\right.\)