Question

a^2+b^2+c^2=13 and ab+bc+ca=6find the value of a^3+b^3+c^3-3abc

Answer 1

(a+b+c)²=a²+b²+c²+2(ab+bc+ca)
=13+2(6)
13+12
=15
so ,a+b+c=√15
a³+b³+c³–3abc=(a+b+c)(a²+b²+c²–(ab+bc+ca))
√15)(13-6)
7√15