Question

(a+3b)=6,show that,a^3+27b^3+54ab=216

Answer 1

(a+b)^3=a^3+b^3+3a^2b+3ab^2
a=a
b=3b
(a+3b)^3=6^3
a^3=a^3
b^3=b^3
3a^2b=9a^2b
3ab^2=27ab^2
6^3=216


a^3+27b^3+54ab=216