解方程组2x-3y=2, (y-1) 4=(4x 9 )20-1

两式相加3（x+y）-3(x-y)=46y=4xy=2/32x+2y-x+y=3x+3y=3x=3-3y=3-2=1

x+y/3+x-y/2=63(x+y)-2(x-y)=282x+2y+3x-3y=363x+3y-2x+2y=285x-y=36x+5y=285x-y=365x+25y=14026y=104y=4x=

3x+y=k①x+3y=2②②乘以3,得3x+9y=6③③减去①,得8y=6-ky=(6-k)/8将y=(6-k)/8代入②中,得x+3(6-k)/8=2x=2-3(6-k)/8因为x,y

y=3(x-y),x=2(x-y)x=0y=0再问：请问，怎样解=0，要过程，谢谢再答：y=3(x-y)=3x-3y4y=3xy=3x/4x=2(x-y)=2x-2y=2x-3x/2=x/2x-x/2

5x+y=369y-x=2即45y-10+y=36y=1x=7

.死算呗xy-2x+3y-6=xy+10x-3y-30,2x-y=4xy+3x+y+3=xy+12x-2y-24,3x-y=92式减1式,x=5,y=6

合并方程组：x+y/2=3x-2y;3x-2y=10+6x+y/4;得出：x=5y/4;从而算出：x=-25/12,y=-5/3.手机打很累.

(x+y)/2+(x-y)/3=6①5(x+y)-2(x-y)=4②由①得3x+3y+2x-2y=365x+y=36y=36-5x③由②得5x+5y-2x+2y=43x+7y=4④③代入④得3x+25

2(x-y)/3-x+y/4=-1（1）6(x+y)-4(2x-y)=16（2）（1）方程两边同乘以12得8（x-y）-3(x+y)=-12合并同类项得5x-11y+12=0(3)(2)合并同类项得1

方程组整理得：2(x+y)-3(x-y)=3①4(x+y)+3(x-y)=15②①+②得x+y=3③，把③代入①，得x-y=1④，③+④得：x=2，③-④得：y=1，则原方程组的解是x=2y=1．

先将第一个等式整理得12X+Y=36,第二个等式整理得-X+9Y=2,由第一个等式得Y=36-12X,通过换元法得-X+9(36-12X)=2,解出X=322/109,再把X=322/109代入-X+

设X+Y=A,则由a(a-3)=10得出(a-5)(a+2)=0,得a=5或a=-2.然后再分2种情况分别代入前面方程式.就能求出X、Y分别是多少了我觉得我这方法是最好解的方法了.

｛3x-4y(x-y)=3,2x-3y=12x-3y=1,得x-y=(1+y)/23x-4y(x-y)=3,代入x-y=(1+y)/2,得3x-2y(1+y)=33x-2y-2y²=34y+

∵3/x+y+2/x-y=6∴x＋5y=28∵3（x+y)-2(x-y)=28∴x=5/6∴y=163/30

若3x>y则方程互相矛盾,所以3x＜>y,解得x=9/10,y=21/5

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

解将x+y=3代入1/2(x+y)-3y=5∴1/2×3-3y=5∴3y=3/2-5∴3y=-7/2∴y=-7/6∴x=25/6

y=x-3代入方程2y+3x-3y=112(x-3)+3x-3(x-3)=112x-6+3x-3x+9=112x=8x=4y=x-3=1

展开x^2-2y^2-xy=-5x^2-2y^2+xy=7所以x^2-2y^2=1xy=6上式除以下式,解分式方程x/y=3/2或-4/3(舍去)所以x^2=9y^2=4x=3y=2或x=-3y=-2

可能是0＜X0=X0≤X≤1X＞1当0＜X时,｜X+Y｜=1原式=Y-X=1Y=1+X｜X｜+2｜Y｜=3变2（1+X）-X=3X=1所以Y=0当0=X时Y无解,不成立.当0≤X≤1时X+Y=1X+2