5x-7y-5=0 3x-2y=-8
y-3x=2,y-5x=4,y-7x=6,y-9x=8,y-11x=0方程组,
已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)
{2x+y/3-2y=0 2(2x+y)-5=7y
(4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuai
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
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
3x-2y=9 x-3y=2 x+y=5 x+2y=3 y=x 2x+y=8
若3x-5y=0,则x+y/x=(),x-y/y=(),2x-3y/2x+3y=( )
已知x.x+y.y-6x-8y+25=0,求3x.x+5y的值
3x+2=y 5X+4=Y 7X+6=Y 9X+8=y 11x=y要如何计算
3x+2=y 5x+4=y 7x+6=y 9x+8=y 11x=y