若x-2y=5,则式子12-x+2y=.以知3x-4y=2x+y则x∶y=
若x-2y=5,则式子12-x+2y=.以知3x-4y=2x+y则x∶y=
已知x-y=-3y+5,则式子x+2y-1的值是?
若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于
已知x*x+4x+y*y-2y+5=0,则x*x+y*y=?
已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)
若3x-5y=0,则x+y/x=(),x-y/y=(),2x-3y/2x+3y=( )
若5x+3y=3x+4y=x+2y+6,则x+y=___
若x/y=4/3 则3x+2y/2x-5y=
3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27
若式子(X-Y+3)的平方与2Y+X的绝对值是相反数,则X=?.Y=?
已知3x-y=2x-3y+5,则式子x+2y-1的值是多少?
设x>1,y>0,若x^y+x^-y=2根号2,则x^y-x^-y等于