Question

If a+b+c=15, ab+bc+ca=50 then a²+b²+c²=?

Answer 1

Answer:

a²+b²+c²= 175

explanation

formula: (a+b+c)²= a²+b²+c²+ab+bc+ca

(a+b+c)²=15² = 225.

ab+bc+ca= 50

apply the formula : (a+b+c)² = a²+b²+c²+ab+bc+ca

225= a²+b²+c²+50

225 - 50 = a²+b²+c²

175 =a²+b²+c²