Question

If a+b+c=5 and ab+bc+ca=10,then prove that a3 +b3+c3-3abc=-25

Answer 1

Prove that a3 +b3 +c3 – 3abc = -25

given that

Answer 2

Answer:

Step-by-step explanation:

WKT,

a3+b3+c3-3abc=[a+b+c][a2+b2+c2-ab-bc-ca]

-25=[5] [(a+b+c)^2 -2ab-2bc-2ca -ab-bc-ca]

-25=(5)(5^2 -3(10))

-25=5(25-30)

-25=5*-5

-25=-25

Hence proved