Question

若(a+b)的平方=25,a的平方除以b的平方=16,请计算下列各式的值:(1)ab(2)a-b

Answer 1

(a + b)² = 25

a² / b² = 16

a = 4 ,b = 1 :ab = 4 ,a - b = 3

a = -4 ,b = -1 :ab = 4 ,a - b = -3

a = 20/3 ,b = -5/3 :ab = -100/9 ,a - b = 25/3

a = -20/3 ,b = 5/3 :ab = -100/9 ,a - b = -25/3