啊..若︱x-y+3︱与︱x+y-1999︱互为相反数,求（x+2y）/（x-y）的值

啊..若︱x-y+3︱与︱x+y-1999︱互为相反数,求（x+2y）/（x-y）的值 若|x+3|与|2y-3|互为相反数,求x+y:x-y的值如题 若｜x-y-5｜与｜2x+3y-15｜互为相反数,则x+y＝? 若|x-3|与|y+5|互为相反数求x+y/x-y的值 若／X+Y-9／+（2X-Y+3)=0求X与Y的值 x-y与y/x-y通分 若|x-y+3|与|x+y-2013|互为相反数,求x+2y/x-y的值. 若|x+y-1|与(x-y+3)的平方,互为相反数,则(x+y)(x-y) 若|x-y-3|与|x+y-2009|互为相反数,求x-y/x+y的值. |x-y+3|与|x+y-1999|互为相反数,求x+y/x-y的值 若根号x-3y+6与绝对值y-5互为相反数,则x+y=?x-y=? 若|x+y|与|2y-3|互为相反数,求2x+y的值. 若|x+y|与|2y-3|互为相反数,求2x+y的值 若|x+y|与|2y-3|互为相反数,求2x+y的值 (3x-y)(3y+x)-(x-y)(x+y) 若|3-x|与|x+y|互为相反数,求(x-y)/xy的值. 若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 判断下面每题中的两种量成什么比例,并说明理由1.若y=3x,则x与y（ ）2.若x分之三=y,则x与y（ ）3.若x-y=0,则x与y（ ）4.若4x=3y,则x与y( )5.若4分之x=y分之3,则x与y( )6.若4分之x=y分之3,则x与y( )