Question

FIND THE VALUE OF A3+ B3 + C3 - 3ABC WHEN A + B + C = 9 ANDA2 + B2+ C2= 29

Answer 1

A+B+C=9
(A+B+C)2=(9)2=81
A2+B2+C2=29
(A+B+C)2=A2+B2+C2+2(AB+BC+AC)
81=29+2(AB+BC+AC)
52=2(AB+BC+AC)
26=AB+BC+AC
A3+B3+C3-3ABC=(A+B+C)(A2+B2+C2-AB-BC-AC)
=((9)(29-(AB+BC+AC))
=((9)(29-(26))
=(9)(3)
=27