The expression 3x^2 + 10x + 8 can be written in the form (3x + A)(x + B) where A and B are integers. What is the value of A - B?
3x^2 + 10x + 8 =
3x^2 + 6x + 4x + 8 =
2(3x + 4) + x(3x + 4) = (3x + 4)(x + 2)
so (3x + A)(x + B) = (3x + 4)(x + 2).
4 - 2 = 2,
thus our answer is 2.
