若x+y/x-y=6,把x,y的值都扩大二倍,则分式的值为 ;若xy/x-y=6 ,把x,y的值都扩大2倍,则分式的值为 .

问题描述:

若x+y/x-y=6,把x,y的值都扩大二倍,则分式的值为 ;若xy/x-y=6 ,把x,y的值都扩大2倍,则分式的值为 .

若x+y/x-y=6,把x,y的值都扩大二倍,则分式的值为 6 ;若xy/x-y=6 ,把x,y的值都扩大2倍,则分式的值为 12 .解题过程2x+2y/2x-2y=2(x+y)/2(x-y)=x+y/x-y=6xy/x-y=2x*2y/2x-2y=4xy/2(x-y)=2xy/x-y=12