Carcass wrote:
If a + b = 2 and 3a – b = –14, then what is ab?
GIVEN:
a + b = 2
3a – b = –14
ADD the two equations to get: 4a = -12
Solve:
a = -3To find the value of b, take the first given equation (a + b = 2), and replace
a with
-3 to get:
-3 + b = 2
Add 3 to both sides to get:
b = 5So,
ab = (
-3)(
5) =
-15Answer: -15
Cheers,
Brent