Question

y(x+y)+(x+y)(x-y)-x的平方,其中x=-2,y=2分之一

Answer 1

y(x+y)+(x+y)(x-y)-x²=(x+y)[y+(x-y)]-x²=(x+y)x-x²=x²+xy-x²=xy=-4

Answer 2

y(x+y)+(x+y)(x-y)-x²=(x+y)[y+(x-y)]-x²=(x+y)x-x²=x²+xy-x²=xy=-4

Answer 3

x(x+y-1)的平方
等于4