4/5x-3/4y=1 4x-3y+1=0
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=1/3,y=-1/2,求代数式x-(x+y)+(x+2y)-(x+3y)+(x+4y)-(x+5y)+...-(
{3(x+y)+3(y+x)=1,3(x+y)+4(y-x)=-1
{3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1
{4/(x+y)+6/(x-y)=3 {9/(x-y)-1/(x+y)=1
微分方程(1)(y'')^2+5y'-y+x=0;(2)y''+5y'+4y^2-8x=0;(3)(3x+2y)dx+(
若2x-3y+4=0则x(x*x-1)+x(5-x*x)-6y+7
已知X,Y,满足(X+3Y)(X-3Y)=-10(Y^2-6/5)和2X(Y-1)+4(1/2X-1)=0
3x-2y=1 4x-5y
若x^5+x^4y+x^4+x+y+1=0,且3x+2y=1,求x,y的值
化简求值{(x=2y)(5x-2y)-(3x+2y)(3x-2y)]/4x,其中x=2,y=-1
3x+2y/4=2x+y/5=x-y+1/6