Question

a^2 + b^2 = 80 and a - b = 4 then find ab=?​

Answer 1

a-b = 4

(a-b)²= 16

a²+b²-2ab = 16

(a²+b²) - 2ab =16

Given a²+b²=80

80-2ab = 16

2ab = 80-16

ab = 64/2 = 32

ab = 32