Answer:
[tex]\huge\boxed{x^2+7x-120=(x+15)(x-8)}[/tex]
Step-by-step explanation:
[tex]x^2+7x-120\\\\\left\{\begin{array}{ccc}a+b=7\\ab=-120\end{array}\right\Rightarrow a=15,\ b=-8[/tex]
[tex]x^2+7x-120=x^2+15x-8x-120=x(x+15)-8(x+15)\\\\x^2+7x-120=(x+15)(x-8)[/tex]
