已知（x+5y-20）^2+|2x-3y-1|=0,求x+y的值

已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) 已知（x+5y-20）^2+|2x-3y-1|=0,求x+y的值 已知x=2,y=3,求代数式（x-y）*（x-y）^3*(x-y)^5*……*(x-y)^11 已知|2-x|与|x-y+4|互为相反数,求代数式3（x-y）-5（x-y）*2-3（x-y）+（y-x）*2-4(x+y）+3（y-x）的值 已知（x+2）^2+|x+y+5|=0,求3x^2y-[2x^2y-(2xy-x^2y)-4x^2]-xy 化简求值：已知【3x分之2-x+y分之2（3x分之x+y-x-y）】÷5x+3y=0 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+y）2 =2,(x-y)3 =3,求(x+y)7(x-y)2(x+y)3(y-x)4 的值 已知方程组{(X+Y)-3(X-Y)=7,2(X+Y)+(X-Y）=-7}则(X+Y)(X-Y)= 已知|x|=2,|y|=3,|x+y|=-(x+y)求x-y 已知2x-y=3,4x+3y=1,求5y（2x-y）²-2（y-2x）三次方 （x-y）^3×（y-x）^4+（x-y）^2×（y-x）^5 已知2x-y=-3,求代数式5(x-3y)-2(x-7y) 已知x-y=3则5(x-y)-3x+3y-2= 已知x-y=3则5(x-y)-3x+3y-2= 已知5|x+y-3|+(x-2y)²=5,求x+y的值 已知3x-2y/x+y=5/3求x；y的值