Question

已知y=3+xy,求代数式2x+3xy-2y/x-2xy-y的值.

Answer 1

y=3+xy y-xy=3 y(1-x)=3 y=3/(1-x)

1)2x+3xy-2y/x-2xy-y

=2x+xy-2y/x-y

=2x+3x/(1-x)-6/x(1-x)-3/(1-x)

=2x-3/(1-x)+3x/(1-x)-6/x(1-x)

=2x-3+3x+(3x²-6)/x(1-x)

=5x-3+(3x²-6)/x(1-x)

2)(2x+3xy-2y)/(x-2xy-y)

=(2x-4xy-2y+7xy)/(x-2xy-y)

=2+7xy/(x-2xy-y)

=.

不知道括号加的对不对?如果对,再继续.