Question

Which is a factor of 4x2 + 36x + 72?

x + 9
x − 6
x + 3
x + 2

Answer 1

First, find the GCF

4 (x^2 + 9x + 18)

Then, find two numbers that multiply to 18 and add to 9. Your numbers should be 6 and 3. Separate and add x to each number to have a properly factored expression.

(x + 3)(x + 6)

Therefore, your answer should be x + 3 because that is one of your factors.

Hope this helps!