I think we should add condition:

That is: x - 9 \(\ne\)0 <=> x \(\ne\)9

a/ = 4x^2 + 12x + 9

b/ = ( x - 2 ) ( x^2 + 2x + 4 )

This is an equation solver, Dat!

Let me help you:

\(\Leftrightarrow\left\{{}\begin{matrix}25x+10y=95\\-4x-10y=-32\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}21x=63\\2x+5y=16\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}x=3\\2.3+5y=16\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}x=3\\y=2\end{matrix}\right.\)

Tran Quang Linh's answer is right