若2x-2y+3=0.则4x-6y+8=__________我就是要那个方程~

若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于 若5x+3y=3x+4y=x+2y+6,则x+y=___ 【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2= 若x+y=4,则多项式1/2(x+y)+4(x-y)-3（x-y）-3/2(x+y)-x+y值是（） （x+y）/2- x-y/2=6 3(x+y)=4(x-y) x+y/3+x-y/2=6 4(x+y)-2(x-y)=40 {3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1 x+y/2+x-y/3=6,4(x+y)-3(x-y)=-20 {(x+y)/2+(x-y)/3=6 4(x+y)-3(x-y)=-20 4(x+y)-3(x-y)=-20,2/x+y+3/x-y=6 若2x-3y+4=0则x（x*x-1)+x(5-x*x)-6y+7 若x-y不等于0,2x-3y=0,则分式(10x-11y)/(x-y)的值是（）?(10x-11y)/(x-y) =[(8x-8y)+(2x-3y)]/(x-y) =8为什么8X-8Y=8？(10x-11y)/(x-y)=[(8x-8y)+(2x-3y)]/(x-y)=8+(2x-3y)]/(x-y)=8+0=8 {x+y=1 ,xy=-6{x(2x-3)=0,y=x²-1{(3x+4y-3)(3x+4y+3)=0,3x+2y=5{(x-y+2)(x+y)=0,x²+y²=8{(x+y)((x+y-1)=0,(x-y)(x-y-1)=0 (x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)= 若2x=3y,则(x*x+y*y)/x*x=? 若2X+3Y-1=Y-X-8=X+6则2X+Y= 若2X+3y-1=y-x-8=x+6,则2x-y=? 若X+6=Y-X-8=2X-3Y-1,则3X-Y=?