Question

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

Answer 1

(a+b+c)^2 = a^2 +b^2 +c^2 +2(ab+bc+ca)

a^2 +b^2 +c^2 =(9)^2-2(40)

=81-80=1

Answer 2

Answer:

Step-by-step explanation:

Given a +b+c =9

ab + bc + ca= 40

(a+b+c+)^2= a^2 + b^2 +c^2+2ab+2bc+2ca

= (a+b+c)^2-2(ab +bc +ca)

=9^2 - 2×40

=81-80

= 1 ans

Hope it will help