Question

what is A^2 +B^2+C^2

Answer 1

Answer:

a2 + b2 + c2 = (a+b+c)^2 - 3abc

Answer 2

so,

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

where

$(a + b + c)^{2}$

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