x² + 5x + 6
x 3
x 2
(x+3)(x+2)
to find this, you must get two numbers (or variables) that will give you the number on the top when multiplied, while giving you the number in the middle when added together.
To prove this, do the FOIL method when you are solve the binomials & make it into a trinomial
x(x) = x^2
x(3) = 3x
x(2) = 2x
3(2) = 6
x^2 + 3x + 2x + 6
x^2 + 5x + 6 (simplify numbers with similar variables)
(x+3) is your answer (in this case, since it does not ask you to choose both, and (x+2) is not a choice
hope this helps