A-B + C = 5, find the value of a ^ 2 + B ^ 2 + C ^ 2-2ab-2bc + 2ca

A-B + C = 5, find the value of a ^ 2 + B ^ 2 + C ^ 2-2ab-2bc + 2ca

a^2+b^2+c^2-2ab-2bc+2ca
=(a-b)^2+2c(a-b)+c^2
=(a-b+c)^2
=25