Question

If a+b+c=9 ab +bc+ca=12 find a2+b2+c2

Answer 1

Please find attached photograph for your answer.

Answer 2

Explanation:

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

Therefore 9^2 = (a^2 + b^2 + c^2) + 2(12).

a^2 + b^2 + c^2 = 81 - 24 = 57.