若[x-y+3]+|2x+y|=0,则x+y=?

若3x-5y=0,则x+y/x=（）,x-y/y=（）,2x-3y/2x+3y=( ) 若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于 若2x=3y,则(x*x+y*y)/x*x=? 若x-y不等于0,2x-3y=0,则分式(10x-11y)/(x-y)的值是（）?(10x-11y)/(x-y) =[(8x-8y)+(2x-3y)]/(x-y) =8为什么8X-8Y=8？(10x-11y)/(x-y)=[(8x-8y)+(2x-3y)]/(x-y)=8+(2x-3y)]/(x-y)=8+0=8 若2x-3y+4=0则x（x*x-1)+x(5-x*x)-6y+7 若x,y满足|2x-y-3|+|3x+2y+1|=0,则x= y= 若线段x ,y 满足[2x-3y]*[3x+2y]=0 则x/y=? 若x,y满足|x-y+1|+(x+y+3)^2=0则x^2-y^2= 若|x+y-3|+(x-y-5)^2=0,则x)^2-y^2= (5)若x/2=y/3(y不为0）则x/y=____,x+y/y=___,y/x-y=___. 若|x|=2,|y|=3,且y/2+x《0则x+y 若[x-y+3]+|2x+y|=0,则x+y=? 若3x-2y=0,则X+y/x-y等于多少? 若y=x(x-1)(x-2)(x-3),则y′（0）= 若|2x-y+5|+(x+2y-4)的平方=0,则（2x-y)的三次方-（x-3y)(y-2x)的平方 若|x-3|+（y+2）=0,则（x-y+4xy/x-y）（x+y-4xy/x+y）的值是 若|x-3|+（y+2）²=0,则（x-y+4xy/x-y）（x+y-4xy/x+y）的值是 若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值