Question

If a2 + b2 + c2 = 38 and a +b+c= 10, find ab + bc + ca​

Answer 1

Step-by-step explanation:

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

10^2 - 38 = 2(ab + bc + ca)

ab + bc + ca = 62/2 = 31