Question 323180
First re-write {{{36-13b+b^2}}} as {{{b^2-13b+36}}} 
Then find two factors of 36 that are negative(b/c your middle term is negative and your last term is positive) that added together give you -13.
-9 and -4
so...
{{{36-13b+b^2}}}
{{{b^2-13b+36}}} 
{{{(b-9)(b-4)}}}