(x+1)^2/9-(y-1)^2/4=1{x-y=1

9y=3x-(x-1),4(x+y)-(2x+4)=8y {3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1 (x-y)/4+(x+y)/5=1/4 (x+y)/9-(x-y)/3=//2(x-y)/4+(x+y)/5=1/4(x+y)/9-(x-y)/3=//2 已知4x=9y求(1)x+y/y (2)y-x/2x有关比例的 解二元一次方程 {3(x+y)-4(x-y)=-9 x+y/2+x-y/6=1 x+y+2(-x-y+1)=3(1-y-x)-4-(y+x-1),x+y=? 先化简再求值 x(9x-y)-y(y-x)+(x-y)的平方,其中x=-1,y=2 常微分方程的通解dy/dx=(x-y+1)/(x+y-3)y^4=2y^n+y=0y''+6y'+9y=e^(-3x)y''+y'-2y=4e^(2x) 化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1 先化简 再求值 (2x-y)(y+x)-(x-2y)(2y+x)-(-3y+x)^2其(√x+1)+y^2+4=-4y 已知:【(x²+y²)-(x-y)²+2y(x-y)】/4y=1,求4x/4x²-y²-1/2x+y 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 化简(x+y)+(2x+1/2y)+(3x+2/3y)+(4x+3/4y)+...+(9x+8/9y)=? (7x-2y)(3x-2y-1)-(4x+3y)(9x+6y)其中x=2y=1 [(y-2x)(-2x-y)-4(x-2y)²]*2y,其中x=1,y=2 [(x+y)(x-y)-(x-y)^2-4xy]/2y,其中x=1,y=-1 [(y-2x)(-2x-y)+4(x-2y)平方]/3y,其中x=1,y=-3