若|x-1|+|y+2|=2,求x+y的值若|a|=3,|b|=6,且a,b异号,求a+b的值已知（a+1）^2+(2b-3)^2+|c-1|=0,求3c分之ab+b分之a-b

若x*x+y*y=x+y-1/2,求x,y的值如题 若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 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. 已知x+y=a,2x-y=-2a,求[（x/y-y/x)/(x+y)-x(1/x-1/y)]/[(x+1)/y]的值 若x-y=2(x+y),求代数式x-y/x+y+x+y/x-y求代数式 x+y分之x-y+x-y分之x+y 已知:y=ax的3次方+bx+3,当x=-1/2时,y=-7,试求x=1/2时,y的值 若x-y=3,x^2-y^2=1,求x+y的值 若x、y满足2x+y=6,x-3y=1,求7y(x-3y)²-2(3y-x)³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.y满足x+=4和x-y=2,求xy分之2x-y+1除以-x分之y+y分之x的值 已知x-y=1,求[(x+2y)^2+(2x+y)(x-4y)-3(x+y)(x-y)]除以y的值大神们帮帮忙 已知x-y=1,求[(x+2y)²+(2x+y)(x-4y)-3(x+y)(x-y)]÷y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(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+y=-6,求[(x+y)的2次方-(x-y)的2次方+2y(y-x)]乘以1分之4y y=(1+x^2)的x次方,求y ' 求y‘-(1/x)y=x^2 的通解 若1/x-1/y=2,求(3x-2xy-3y)/(x-2y-y)的值 已知x-y=3,求[（x+y)(x-y)-(x-y)^2+2y(x-y)]除以的值