4x-3y=12,3x+2y=12,

已知2x-y/x+3y=2,求代数式4x-2y/x+3y减4x+12y除以2x-y 已知2x-y/x+3y=2,求代数式4x-2y/x+3y减4x+12y/2x-y的值 已知2x-y/x+3y=2,求代数式4x-2y/x+3y减4x+12y/2x-y的值 12y(x-y)^2-8(x-y)^3=? 3x+y=2 -y/x+y=123x+y=2 （-y/x）+y=12 (x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)= 解方程组：x+y/2+x-y/3=6 4(x+y)-5(x-y)=12 解方程组{2(x-y)/3 - x+y/4=-1 6(x+y)-41(x-y)=12 8（x-y)=3（x+y)-12 6（x+y)=4（2x-y)+16 8（x-y)=3（x+y)-12 6（x+y)=4（2x-y)+16 X×X-2XY-Y×Y+2X-2Y+2=02X×2X-4XY-2Y×2Y+3X-3Y+4=0X×X+2XY+Y×Y+X+Y-56=0X×X-2XY+Y×Y-X+Y-12=0X×X-3XY+Y×Y=-13X×3X-XY+3Y×3Y=13 两个在一起的方程之间有所联系（要求一步一步写出来） 4(x+2)=1-5y 4(x+y)-3(x-y)=12 4-12(x-y)+9(x-y)² =(2-3x+3y)² 先化简再求值; 解方程组 x(x-y)-y(x+y)+2xy 其中x=2 ,y=-22.x[x-x(x-1)],其中x=-2解方程组4x+3y=12x-y=32.y+1=2x 4x-y=2 3.2x+2y=0 2x-y+24=0 根据x=3y填表 x=3 x=?x=18 x=?x=90 x=?x=?y=?y=2 y=?y=4 y=?y=12 y=2.5不对！是x=3 y=？x=？y=2 x=18 y=4，x=？y=4，x=90 y=？x=？y= 12，x=？y=2. 3y=2x y/3=x/2 12/x=9/y y/x=?y/x=?x/y=? 21/(x+y)+4/(x-y)=12/(x+y)+7/(x-y)结果为(x+y)/(x-y)=3求过程! 若x+y=4,x^3+y^3=(x+y)(x^2-xy+y^2)z,求x^3+12xy+y^3的值.