2x-1 5 3y-2 4=4,3x 1 3 3y 2 4=0

原式=(9x²+24xy+16y²-4x²+y²-5x²+6xy-y²)÷(-2y)=(30xy+16y²)÷(-2y)=-15x

(1)=(x-y)(x+1)(x-1)(2)=x(x^2+x+1/4x)=x(x+1/2)^2(3)=4x^2+4xy+y^2-x^2+4xy-4y^2=3x^2+8xy-3y^2=(3x-y)(x+

由2(X+Y)3X+3Y=24得：2(X+Y)X+Y=8①;(X+Y/2X)XY/2Y=1得：X+Y=4②;由①、②得出Y=8(1-X),进入②知X=4/7；即Y=24/7

写清楚点点比如说前面是X/X还是X/(X-Y)打上括号分段这样才能清楚的做

由(1)得3x+3y+2x-2y=365x+y=36(3)由(2)得4x+4y-3x+3y=-20x+7y=-20(4)(3)×7-(4)得34x=272∴x=8把x=8代入(3)得y=-4∴x=8y

(2x-y)(2x+y)+(2x-y)(y-4x)+2y(y-3x)=4x^2-y^2+2xy-8x^2-y^2+4xy+2y^2-6xy=-4x^2=-4(-1/4)^2=-1/4

{(x+y)/2+(x-y)/3=63(x+y)+2(x-y)=36(1)4(x+y)-3(x-y)=-20(2)由（1）*3+(2)*2得9(x+y)+6(x-y)+8(x+y)-6(x-y)=36

2x-y/x+3y=2得x+3y/2x-y=1/24x-2y/x+3y减4x+12y除以2x-y=2(2x-y)/x+3y-4(x+3y)/2x-y=2乘以2-4乖以1/2=4-2=2

化简得：-x+7y=11①7x+3y=27②①式×7得：-7x+49y=77③②+③得：52y=104∴y=2代入①得：x=3∴x=3,y=2再问：亲，是代入法哦！再答：代入法①式得3x+3y-4x+

楼上的全错,{(3x+y)(3x-y)-(x-5y)(5x-y)-(x-2y)²}÷(-4x)={9X²-(5x²-xy-25x²+5y²)-(x&s

答案是2.4x-2y/x+3y=(2x-y/x+3y)乘以2=4,4x+12y/2x-y=(x+3y/2x-y)乘以4=1/2x4=2,所以代数式等于4-2=2.

x-(x+y)+(x+2Y)-(x+3y)+(x+4y)...-(x+2009y)=-y+2y-3y+4y+...-2007y+2008y-2009y=1004y-2009y=-1005y=-1005

3x^2+xy-2y^2=0推出(3x-2y)(x+y)=0推出x=-y或x=(2/3)y{(x+y)/(x-y)+4xy/(y^2-x^2)}/{(x+3y)*(x-y)}/x^2-9y^2推出：{

第二个方程是不是写错了2/（x+y）+3/（x-y）=6是这样吗

3(x+y)-4(x-y)=4(x+y)/2+(x-y)/6=1令a=x+y,b=x-y3a-4b=4(1)a/2+b/6=1则3a+b=6(2)(2)-(1)5b=2b=2/5a=(6-b)/3=2

x（x*x-1)+x(5-x*x)-6y+7=-x+5x-6y+7=2(2x-3y)+7=2*(-4)+7=-8+7=-1再问：能在写详一点吗-x+5x-6y+7再答：x（x*x-1)+x(5-x*x

解9y=3x-(x-1)2x-9y+1=0①4(x+y)-(2x+4)=8y2x-4y-4=0②②-①得：5y-5=0∴y=1将y=1代入①得：2x-9+1=0∴x=4∴方程的解为：x=4,y=1

（2x^3y^3+x^4y^2+x^2y^4)^2-x^2y^2(x+y)^2=x^2y^2（x^2+2xy+y^2)-x^2y^2(x+y)^2=x^2y^2(x+y)^2-x^2y^2(x+y)^

原式=x-x+x-x+……-x+(2-1+4-3+5-4+……+2008-2007-2009）y=0+(1×1004-2009)y=-1005y=1005/2

我把方法告诉你,最后的答案你自己做吧,很容易.(x+y)(x+2y)(x+3y)(x+4y)=-40(x+y)（x+4y）(x+2y)(x+3y）=-40(x^2+5yx+44)(x^2+5yx+66