Question

Find the value of a3 + b3 +c3 – 3abc, when a + b + c = 8 and a b + b c + c a = 25.​

Answer 1

Step-by-step explanation:

First we find the value of a

2

+b

2

+c

2

a

2

+b

2

+c

2

=(a+b+c)

2

−2(ab+bc+ca)=8

2

−2×19=64−38=26

∴a

3

+b

3

+c

3

−3abc=(a+b+c)(a

2

+b

2

+c

2

−ab−bc−ca)=(8)(26−19)=8×7=56

Answer 2

Step-by-step explanation:

This is an example so that u can do ur know

First we find the value of a

2

+b

2

+c

2

a

2

+b

2

+c

2

=(a+b+c)

2

−2(ab+bc+ca)=8

2

−2×19=64−38=26

∴a

3

+b

3

+c

3

−3abc=(a+b+c)(a

2

+b

2

+c

2

−ab−bc−ca)=(8)(26−19)=8×7=56

Hope it helps u