Question

evaluate using suitable identity : (3.2)^3-(2.2)^3-1^3.

Answer 1

if a+b+c=0 then a³+b³+c³ = 3abc
here a = 3.2
b= 2.2
c= 1
3.2+(-2.2)+(-1) = 3.2-2.2-1 = 0
then
(3.2)³-(2.2)³-(1)³ = 3(3.2)(2.2)(1) = 21.12
Hope this helps