Question

(x-1).(x+1)=8

Answer 1

\(\left(x-1\right)\left(x+1\right)=8\)

\(\Rightarrow x^2-1^2=8\)

\(\Rightarrow x^2-1=8\)

\(\Rightarrow x^2=9\)

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

Answer 2

(x-1)(x+1)=8

=>x²-1=8

=>x²=9

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