Question

if a+b+c=9 &ab+bc+ca= 40 find a^2+b ^2+c^2

Answer 1

Hello Mate!

Please refer to attatchment!

Answer 2

(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 = 81-80= 1 Ans.