Question

m - n = -2 and m^3 - n^3 = -26, find mn

Answer 1

We Know,

m^3 -n^3 = (m- n)^3 + 3mn (m - n)

Given here,

m- n = -2 and m^3 - n^3 = -26

m^3 - n^3 = (m - n)^3 +3mn (m -n)

=> -26 = (-2)^3 + 3mn (-2)

=> -26 = -8 - 6mn

=> -6mn = -26 + 8

=> - 6mn = -18

=> mn = -18/ -6

=> mn = 3

Ans: mn = 3