Question

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

Answer 1

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

`x^2+x-2-x-2=0`

`(x-2).(x+2)=0`

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

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

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Answer 2

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

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

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

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

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

\(\Rightarrow x=\pm2\)