Question

ab+bc+ca=?,a^2+b^2+c^2=50,a+b+c=2

Answer 1

Answer:

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

Or, (2)^2=50+2(ab+bc+ca)

Or, ab+bc+ca=(4-50)/2=-46/2=-23