Question

if x-y=4 and xy=2 then find the value of x^3-y^3

Answer 1

(x-y)=4

(x-y)²=16

x²+y²-2xy=16

x²+y²-2.2=16

x²+y²=20

Now

x³-y³=(x-y)(x²+y²+xy)

x³-y³=4(20+2)

=4.22=88