(2/2)3x-2)=4(x-5),3(y+2)-2=2y-(y+5),3[y-2(y-1)]=4y这六道题方程怎样解

解方程x+y+(x+y/2)=15 3x+5y+4(x+y/2)=62 化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1 3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) 已知x=1/3,y=-1/2,求代数式x-(x+y)+(x+2y)-(x+3y)+(x+4y)-(x+5y)+...-( 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 {3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1 (4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuai 解方程3y^2-(2y+1)(y-2)=(y-5)(y-1) 解方程：3y^2-(2y+1)(y-1)=(y-5)(y+1) 4x-2y-6y*-y-3x+5y* *=2 就是平方