B ^ 2 + C ^ 2 + 2Ab + 2BC + 2Ac factorization

B ^ 2 + C ^ 2 + 2Ab + 2BC + 2Ac factorization

b^2+c^2+2ab+2bc+2ac
=a^2+b^2+c^2+2ab+2bc+2ac -a^2
=(a+b+c)²-a²
=(2a+b+c)(b+c)