解方程3(x-1)-4y=8,2(y-3)=2(x+1)-14 已知(x-y)/4=(2x+y)/5,且2x-3y=18
解方程3(x-1)-4y=8,2(y-3)=2(x+1)-14 已知(x-y)/4=(2x+y)/5,且2x-3y=18
已知x=1/3,y=-1/2,求代数式x-(x+y)+(x+2y)-(x+3y)+(x+4y)-(x+5y)+...-(
已知:3x=8y.求(1)x+y/y (2)2x+3y/x-2y
设函数y=y(x)满足微分方程y″-3y′+2y=2e^x 且曲线y=y(x)在(0.1)处与已知曲线y=x^4-x+1
已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)
3x+3y=k+1x+y=3已知x,y是方程的解且2
已知x,y∈R,且x,y满足方程x^2+4y^2=1,试求3x+4y的最大值
{3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1
化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1
已知x+y+2(-x-y+1)=3(1-y-x)-4(y+x-1),则x+y等于( )
先化简再求值(x-y)(x+y)-(x-2y) 的完全平方+x(3x-5y)-(x-y)(x-2y),其中x=1/2 y
已知X-Y/X+Y=3,求代数式2(x-y)/X+Y-3X+Y/X+Y