11x-4y=180

3x+2=y和11x=y,得到x=1/4,y=11/4,5X+4=Y和7X+6=Y,得到X=-1,Y=-1代入9X+8=y,不成立,方程组无解..

3(x+y)+3(y-x)=1(1)3(x+y)+4(y-x)=-1(2)(2)-(1)得y-x=-2(3)代入（1）3（x+y)-6=1x+y=7/3=>x=7/3－y又由（3）得x=y+2y+2=

x+2y=-5＆2x-5y=-1由2式得：x=1/2×(5y-1)；代入1式得：1/2×(5y-1)+2y=-5;y=-9/13;再代入1式得x+2×(-9/13)=-5得：x=-3×8/13

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+

将11x=y即y=11x分别代入前面四个方程式,1、方程式一得3x+2=11x,x=1/4,则y=11/4；2、方程式二得5x+4=11x,x=2/3,则y=22/3；3、方程式二得7x+6=11x,

(3x+2y)(4x-5y)-11(x+y)(x-y)+5xy=12x²-7xy-10y²-11x²＋11y²＋5xy=x²-2xy＋y²=

第二个方程是不是写错了2/（x+y）+3/（x-y）=6是这样吗

方程化为－x+7y=1117x+3y=272将1式化为x=7y-113则将3式代入2式可得7（7y-11）+3y=2752y=104y=2x=7×2-11x=3所以解得x＝3y＝2

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

最后一个应该是：y-11x=10吧这样解就是X=-1,Y=-1否则无解

1、3x-2y=32x+2y=176x-4y=66x+6y=5110y=45y=4.5x=42方程无解3、x+3y=62x-3y=32x+6y=122x-3y=3y=1x=34、2x+3y=11y-2

（5x+3y)(3y-5x)-(4x-y)(4y+x)=(3y)^2-(5x)^2-(4x^2+15xy-4y^2)=9y^2-25x^2-4x^2-15xy+4y^2=13y^2-15xy-29x^

-7再问：继续把过程写给我，就采纳你的意见再答：x=-(2+8y)/9则带入4x+5y=-11得到-7

(3x-2y)(4x-5y)-11(x+y)(x-y)+5xy=12x^2-23xy+10y^2-11x^2+11y^2+5xy=x^2-18xy+21y^2=x^2-10xy+21y^2-8xy=(

x+y/3=x-y/4⑴2x+3y=11⑵由⑴得x+7y=0,x=-7y(3)将(3)代入⑵得y=-1所以x=7

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

4x²y-3y²=7.(1)3x²y+4y²=19.(2)(1)*2+(2):11x^2y-2y^2=14+19=33

3x+2=y5x+4=y7x+6=y9x+8=y有解x=-1,y=-111x=y按前面的规律,是不是少加了一个10?应该是11x+10=y?是的话,解就是x=-1,y=-1了