7x-3y=-1 10x+3y+1=0 4x-5y=-17 4x+5y+8=0
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
x1:4x-3y=8;y=7-5x;2:2x-7y=8,3x-8y-10=0;3:4x-y=-1;4:5x-10y+15
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)+...-(
若|y+5|+(5x+1)^2=0,求-3(2x-y)-{7x-[6x+2y-(10x-8y)]-x-2(3x-4y)}
(4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuai
y-3x=2,y-5x=4,y-7x=6,y-9x=8,y-11x=0方程组,
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
若x^5+x^4y+x^4+x+y+1=0,且3x+2y=1,求x,y的值
{3(x+y)+3(y+x)=1,3(x+y)+4(y-x)=-1