Question

if a+b+c=9,ab+bc+ca=26 then whats a^2+b^2+c^2

Answer 1

Given->a+b+c=9,ab+bc+ca=26

To find->a^2+b^2+c^2 Solution->(a+b+c)^2=a^2+b^2+c^2+2(ab+bc+ca)

(9)^2=a^2+b^2+c^2+2(26)

81=a^2+b^2+c^2+52

a^2+b^2+c^2=81-52

a^2+b^2+c^2=29