Question

x^2-16/x-9 . x^2+x-90/x^2+14x+40

Answer 1

\(\large \begin{array}{cccl}
x^2&+x&-90\\
&\uparrow &\uparrow \\
&10-9&10\cdot -9
\end{array}\qquad
\begin{array}{cccll}
x^2&+14x&+40\\
&\uparrow &\uparrow \\
&10+4&10\cdot 4
\end{array}\)

can you factor those 2 fellows out? what do you think?