Question

what is the a²+b²+c² formula ?

Answer 1

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

Answer 2

Hey there!
We know that,
( a + b + c) ² = a² + b² + c² + 2ab+ 2bc + 2ca

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

Hope helped!