[y(x-y)+x(x+y)-x²]÷(-y)要过程
问题描述:
[y(x-y)+x(x+y)-x²]÷(-y)要过程
答
[y(x-y)+x(x+y)-x²]÷(-y)
=(xy-y^2+x^2+xy-x^2)÷(-y)
=(2xy-y^2)÷(-y)
=-2x+y