[질문] x²+x²=? 이거공식좀알려주세요

x²+x²=2x²//(a+b)(a-b)=a²-b²//x³+y³=(x+y)(x²-xy+y²)//x³-y³=(x-y)(x²+xy+y²//x²+y²=(x-y)²+2xy=(x+y)²-2xy//