若|x-3|+|y+5|+|2+7|=0求x-y-2的值

若2x-3y+4=0则x（x*x-1)+x(5-x*x)-6y+7 若3x-5y=0,则x+y/x=（）,x-y/y=（）,2x-3y/2x+3y=( ) (5)若x/2=y/3(y不为0）则x/y=____,x+y/y=___,y/x-y=___. {2x+y/3-2y=0 2(2x+y)-5=7y 若x>0,y>0,且√x(√x+√y)=3√y(√x+5√y),求2x+2√x*√y+3y/x-√x*√y+y 若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于 若|x+y-3|+(x-y-5)^2=0,则x)^2-y^2= 若2x-3y=0,求5x+4y/3x-2y 若 (3x+4y-1)^2+|3y-2x-5|=0,则x+7y 若/5x-7y-3/+(x-2y)的平方=0,则x=?y=? 若|3x-y-7|+(5x+2y-8)的二次方=0,则x-y=? 若(x*x+y*y)(x*x+y*y)-4x*x*y*y=0,求代数式(x*x+5xy+y*y)/(x*x+2xy+y*y)的值 已知7x+5y/2y-x=3/2,且x≠0,求X/x-4y 若｜y+5｜+(5x+1)2=0,求-3(2x-y)-｛7x-[6x+2y-(10x-8y)]-x-2(3x-4y)｝的值 若|y+5|+(5x+1)^2=0,求代数式-3(2x-y)-{7x-[6x+2y-(10x-8y)]-x-2(3x-4y)}的值 若｜y+5｜+(5x+1)^2=0,求-3(2x-y)-｛7x-[6x+2y-(10x-8y)]-x-2(3x-4y)｝的值 已知(3x+1)(3x-3)-3x+2)^2=-7,(y+7)(y-7)-y(y-7)=0,求8y^2-5y(-y+3x)+4y(-4y-5/2x)的值 y-3x=2,y-5x=4,y-7x=6,y-9x=8,y-11x=0方程组,无