Question 225077
GCF is {{{x^3y}}}
{{{x^3y(x^2y^2-9xy+20)}}}
Factor what's left in the parentheses:
{{{x^3y(xy-5)(xy-4)}}}
The End. Enjoy.
:-)

Okay, the answer to the next one:
{{{3x^2 + 23x – 36}}}
I used the ever so fun AC method. Take the A term (3) and the C term (36), multiply them together and find a factoring that adds to give you 23.
So, 3*36=108.
A factor of 108 is 27*4.
If we have a positive 27 and a negative 4, we can get to 23. (27-4=23).
So, we rewrite the middle term and our equation becomes:
{{{3x^2+27x-4x-36}}}
Then we factor by grouping:
{{{3x(x+9)-4(x+9)}}}
Pull out the common factor {{{(x+9)}}} gives us:
{{{(3x-4)(x+9)}}}
Hope that helps.
:-D