x+y分之x²+x+y分之y²+2xy等于多少

问题描述:

x+y分之x²+x+y分之y²+2xy等于多少

x²/(x+y)+(y²+2xy)/(x+y)
=(x²+y²+2xy)/(x+y)
=(x+y)²/(x+y)
=x+y