Answer:
x ≠ -5
Step-by-step explanation:
The easiest way is to factor the numerator.
x2 + 9x + 20 = (x + 4)(x + 5)
Then
(x2 + 9x + 20)/(x + 5) = (x + 4)(x + 5) / (x + 5) = x + 4,
with the restriction that x ≠ -5
