Question 171342
{{{a^2b+2ab-15b}}}


First, you have a {{{b}}} in every term, so factor that out:


{{{b(a^2+2a-15)}}}


Second, note that {{{5*-3=-15}}} and {{{5-3=2}}}, so


{{{(a+5)(a-3)=a^2+2a-15}}}, and therefore


{{{a^2b+2ab-15b=b(a+5)(a-3)}}}