Answer:
(x+4)(x+5)
Step-by-step explanation:
first you have x^2+9x+20
since there isnt a greatest common factor, you should use the A*C = B/t-chart method
a*c = 1*20=20
b = 9
what factors of 20 add together to equal 9?
factors of 20 = 1, 2, 4, 5, 10, 20
4 and 5
So, you would set the problem like this:
x^2+4x+5x+20
and then factor by grouping
(x^2+4x)(5x+20)
x(x+4) 5(x+4)
then simplify it (the numbers in the parenthesis should end up being the same, if not, an error was made)
(x+4)(x+5)