{x/4+y/2=1/2 3(2x-5)-4(3y+4)=5怎么解

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)-4(x-y)=11,2(x-y)+5(x+y)=27 5x+4y=6 2x+3y=1二元一次方程怎么解 数学题……555{(3x+y)(3x-y)-(x-5y)(5x-y)-(x-2y)²÷(-4x),x=-2.y 解方程组：（0.2x+0.1y）/2- （4x-y）/10=（x-y）/5+ (3x+0.5y)/30 (3x+2y-1 3x-2y=1 4x-5y （x+2)(x+3) (x-4)(x+1) (y+4)(y-2) (y-5)(y-3) {3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1 解方程组{x=2y,x+y=3; {y=1-x,3x+2y=5 ;{3x+5y=5,3x-4y; {2分之x-3分之y+ (4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuai 3(x+y)+2(x-y)=36 4(x+y)-5(x-y)=2 解方程组