Answer:
The solution set is {-8, 5}.
Step-by-step explanation:
a^2 + 3a – 40 = 0 .
We need 2 numbers whose product is -40 and whose sum is +3.
They would be + 8 and - 5, so we have the factors:
(a + 8)(a - 5) = 0
Now either a + 8 = 0 or a - 5 = 0, so:
a = -8 or 5.
