若|x-2|+|y-3|=0,求2x-y的值.∴也要用。例如：∵******，∴******。原式=******当*=*时原式=**********

若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 若根号x+y-3+绝对值xy+x+y-2=0,求x/y+y/x根号x+y-3+绝对值xy+x+y-2=0,求x/y+y/x 若x+y+3=0,求2/3-2x-2y+(-x-y)^2 若2x-3y=0,求5x+4y/3x-2y 若／X+Y-9／+（2X-Y+3)=0求X与Y的值 若X,Y互为相反数,且(X+Y+3)(X-Y-2)=0,求X,Y的值? 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 若x>0,y>0,且√x(√x+√y)=3√y(√x+5√y),求2x+2√x*√y+3y/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(2x-y-1)2+|x-2y-3|=0,求代数式(2x+y)(2x-y)-(x+2y)(x-2y-1)的值若(2x-y-1)²+|x-2y-3|=0,求代数式(2x+y)(2x-y)-(x+2y)(x-2y-1)的值 若x^2-4x+y^2-10y+29=0,求x^2y^2+2x^3y^2+x^4y^2的值 已知x-y=3,求[（x+y)(x-y)-(x-y)^2+2y(x-y)]除以的值 已知3x =2y 求x/x+y+y/x-y-y²/x²-y² 已知x-3y=0,求(2x+y)/(x^2-2xy+y^2)X(x-y) 若(x+y)(x+y-1)-2=0,求x+y的值求 若|x+y-1|+（x-y-2)²=0,求代数式（x+2y)(x-2y）-（2x-y)(-y-2x)的值. 若x-y/x+y=5,求x-y/2x+2y+5x+5y/3x-3y的值 求导数y=3x-x^2 求y',y'/ x=1 y'/x=0