x/2=y/3,5x+2(y-8)=0

已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) 【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2= (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+( 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=( ) y-3x=2,y-5x=4,y-7x=6,y-9x=8,y-11x=0方程组, 6(x-y)-2(x+y)=14 3(x-y)+(x+y)=5 3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27 已知x*x+4x+y*y-2y+5=0,则x*x+y*y=? {2x+y/3-2y=0 2(2x+y)-5=7y