Question

If a+b+c=5 a^2+b^2+c^2=29 find the value of a^3+b^3+c^3-3abc

Answer 1

a=5-b-c
a2=(5-b-c)2
(5-b-c)2

Answer 2

Answer:

155

Step-by-step explanation:

A+b+c= 5 and a 2 + b 2 +c 2 =29, find the value of a 3 +b 3 +c 3 -3abc  

Consider the formula - a³+b³+c³- 3abc = (a+b+c) (a²+b²+c²-(ab+bc+ca))

We have to find ab+bc+ca

given a+b+c = 5

Squaring on both sides we get,

(a+b+c)² = 5²

a²+b²+c² + 2(ab+bc+ca) = 25

2 (ab+bc+ca) = -4

ab + bc + ca = -2

Now, a³+b³+c³-3abc = (a+b+c) (a²+b²+c²-(ab+bc+ca))

Putting the values we get

5(29-(-2))

5 x 31

155