[질문] x제곱-y제곱+2yz-z제곱 인수분해 해설과함께~

x^2 - ( y^2 - 2yz + z^2) = x^2 - (y - z)^2 = {x + (y - z)}{x - (y - z)} = (x + y - z)(x - y + z), // x^2 - y^2 = (x + y)(x - Y)