Question

已知y=3xy+x，求代数式2x+3xy-2y/x-2xy-y的值

Answer 1

y=3xy+x
x-y=-3xy
所以：
x-2xy-y分之2x+3xy-2y
=2(x-y)+3xy/（-3xy-2xy）/
=-6xy+3xy/5xy
=-3xy/-5xy
=3/5

Answer 2

=2x+3xy-2（3xy+x）/x-2xy-(3xy+x)=3/5

Answer 3

xy=(y-x)/3;
(2x+3xy-2y)/(x-2xy-y)=(2x+(y-x)-2y)/(x-2(y-x)/3-y)=3/5