Question

if a-b=6 and a to the power two +b to the power 2 =42 find ab

Answer 1

a - b = 6


Square on both sides,


(a - b)² = 6²

a² + b² - 2ab = 36

42 - 2ab = 36

42 + 36 = 2ab

78 = 2ab

39 = ab