Question

已知,xy/x+y=3,求代数式3x-5xy+3y/-x+3xy-y的值

Answer 1

xy/x+y=3

xy=3(x+y)

3x-5xy+3y/-x+3xy-y

=(3x+3y)-5*3(x+y)/[-x-y+3*3(x+y)]

=-12(x+y)/8(x+y)

=-3/2

望采纳,谢谢!