Consider the trinomial x^2 + 3x − 40. as a first step to factoring it, find the factors of −40 such that the sum of those factors is 3. (enter your answers as a comma-separated list.)
What are factors of -40? (-20)(2) (-10)(4) (sum of these factors is 6, which is not what we wanted) (-5)(8) = -40 and the sum of the factors (-5) and (8) is 3.
{-5, 8} is the list of factors of -40 that add up to 3.
