已知x-y=-3xy,则代数式x-2xy-y/2x-14xy-2y的值为?
问题描述:
已知x-y=-3xy,则代数式x-2xy-y/2x-14xy-2y的值为?
答
x-2xy-y/2x-14xy-2y
=[(x-y)-2xy]/[2(x-y)-14xy]
=(-3xy-2xy)/(-6xy-14xy)
=1/4
答
如果我猜得没有错的话题目应该是求(x-2xy-y)/(2x-14xy-2y)
那么就简单了,原式=(x-y-2xy)/(2x-2y-14xy)
=(-3xy-2xy)/(-6xy-14xy)
=1/4
答
此题主要是把x-y用-3xy代替就可作了
x-2xy-y/2x-14xy-2y
=(-3xy-2xy)/2(x-y)-14xy
=-5xy/(-6xy-14xy)
=-5xy/-20xy
=1/4