已知3^x=2,2^x=3,3^y=4,2^y=5,求:(1)6^2x+y(2)12^2x-y(3)(3^x-2y)-(
已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)
已知:3x=8y.求(1)x+y/y (2)2x+3y/x-2y
已知X-Y/X+Y=3,求代数式2(x-y)/X+Y-3X+Y/X+Y
已知x=1/3,y=-1/2,求代数式x-(x+y)+(x+2y)-(x+3y)+(x+4y)-(x+5y)+...-(
(1)已知x+y=6,x²-y²=5,求x-y的值(2)若x+y=3,x²+y²
已知x=3分之1,y=二分之一,求代数式x-(x+y)+(x+2y)-(x+3y)+...-(x+13y)的值
已知2x-y/x+3y=2,求代数式4x-2y/x+3y减4x+12y除以2x-y
已知2x-y/x+3y=2,求代数式4x-2y/x+3y减4x+12y/2x-y的值
已知2x+3y=2(x>0,y>0),求x+y最大值
已知(x+2)^2+|x+y+5|=0,求3x^2y-[2x^2y-(2xy-x^2y)-4x^2]-xy
已知x/2=y/3=z/4,求下列各式 (1)(x+y+z)/x (2)(x-y+2x/(x-y-2z)
已知xy=2,x-y=3,求(x+y)(x-y)-y^2-(6x^2y-2xy^2)/2y的值.