2x=3-y 3x=2-2y-搜答案-智慧作业帮

[23x−2x+y(x+y3x−x−y)]÷x−yx=[23x−2x+y•x+y3x+2x+y•(x+y)]•xx−y=(23x−23x+2)•xx−y=2xx−y故答案为2xx−y．

3y^2=12y3y^2-12y=03y(y-4)=0y1=0,y2=43x^2-5x=0x(3x-5)=0x1=0,x2=5/3（x+3)^2=2x(x+3)x^2+6x+9=2x^2+6xx^2=

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

设x-y=mx+y=n则6m-2n=143m+n=5解得m=2n=-1即x-y=2x+y=-1解得x=1/2y=-3/2

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

{(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

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+

解方程组2x−5＝y，①3x−2y＝12，②时，把①代入②即可消去y，达到消元的目的；解方程组2x+3y＝133x−4y＝−6时，想法把y的系数化为相同，然后用减法化去，达到消元的目的．故答案是：代入

y的平方+4=6Y公式B平方-4乘A乘CA=1B=-6C=4《A为2次项系数.》即：36-16=20Y=《-B+-根号B平方-4乘A乘C》除以2A最后Y=3+2倍根号5和3—2倍根号5

X+Y分之X-Y等于3x=-2yX+Y分之2(x-y)减X+Y分之3X+Y=(-x-3y)/(x+y)=1

因为(x-y)/(x+y)=3,则(x＋y)/(x－y)＝1/3则5(x-y)(x+y)-(x+y)/2(x-y)＝5*3-1/(3*2)=15-1/6=89/6

第二个方程是不是写错了2/（x+y）+3/（x-y）=6是这样吗

1.15-9y-9x＞-9/43.3(x-1)-x+1212x>32X＞8/3

解(x-y)(x+y)-(x-2y)²+x(3x-5y)-(x-y)(x-2y)=(x²-y²)-(x²-4xy+4y²)+(3x²-5xy

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

若(x-y)/(x+y)=3那么x-y=3(x+y)x-y=3x+3y故x=-2y所以(x+2y)/(6x-7y)=(-2y+2y)/(6*(-2y)-7y)=0如果不懂,请Hi我,祝学习愉快!

[23x-2x+y（x+y3x-x-y）]÷x−yx=（23x-23x+2）×xx−y=2xx−y，∵5x+3y=0，∴y=-53x，∴原式=2xx+53x=34．

很累-3x-2y

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