mathsssssss~!!

a^2 - b^2 = -16………(1)

ab=15…….(2)

From (2)
a = 15/b………(3)

Substitute (3) into (1)
(15/b)^2 – b^2 = -16
225/b^2 – b^2 = -16
225 – b^4 = -16b^2
b^4 – 16b^2 – 225 = 0
(b^2 – 25)(b^2 + 9) = 0
b^2 = 25 or b^2 = -9 (rejected because b^2 must >= 0)
b = 5 or -5

when b=5, a = 15/5 = 3
when b=-5, a = 15/-5 = -3

Therefore a=3 and b=5
Or a=-3 and b=-5

a=3, b=5

a=15/b
a^2=225/b^2
225/b^2-b^2=-16
16=(b^2-225)b^2
16b^2=b^2-225
15b^2=-225
b^2=-15

no solution

a=3
b=5