因为x+y除以xy等于4,所以,x+y=4xy
2x-5xy+2y=2(x+y)-5xy=2*4xy-5xy=3xy
x+2xy+y=4xy+2xy=6xy
所以,2x-5xy+2y除以x+2xy+y的值＝3xy/6xy=1/2