Question

If a+b+c=9 and ab +bc+ ca = 40 find a2+b2+c2

Answer 1

Answer:

We know,

(a+b+c)

2

=a

2

+b

2

+c

2

+2(ab+bc+ca)

9

2

=a

2

+b

2

+c

2

+2×40

81=a

2

+b

2

+c

2

+80

a

2

+b

2

+c

2

=1