Question

If a+b+c=13 and ab+bc+ca=50,find the value of a2 +b2+c2

Answer 1

Explanation:

(a+b+c)2=a2+b2+c2+2(ab+bc+ca)

2(ab+bc+ca)=(a+b+c)2−(a2+b2+c2)=169−69=100=(ab+bc+ca)=50