Question

if a+b+c=9 and a^2+b^2+c^2=35, find the value of a^3+b^3+c^3-3abc

Answer 1

Given(a+b+c)=9
Squaring on both the sides,we get
(a+b+c)=9^2
a^2+b^2+c^2+2(ab+bc+ca)=81
35+2(ab+bc+ca)=81
2(ab+bc+ca)=81-35=46
ab+bc+ca=23-->(1)
Recall that a^3+b^3+c^3=3and=(a+b+c)(a^2+b^2+c^2-ab-bc-ca)
=9(35-23)
=9(12)=108

Answer 2

Answer:

hope it helps a lot mate....