3(x+y)+2(x-y)=36 4(x+y)-5(x-y)=2

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3(x+y)+2(x-y)=36 4(x+y)-5(x-y)=2
3(x+y)+2(x-y)=36 4(x+y)-5(x-y)=2

3(x+y)+2(x-y)=36 4(x+y)-5(x-y)=2
3(x+y)+2(x-y)=36
4(x+y)-5(x-y)=2
5x+y=36
-x+9y=2
解得
y=1,x=7

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3(x+y)+2(x-y)=36=3x+3y+2x-2y=5x+y...............1
4(x+y)-5(x-y)=2=4x+4y-5x+5y=-1x+9y...............2
现在把2式子乘以-5，那么就变成了-10=5x-45y........3
1式子-3式子得到46...

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3(x+y)+2(x-y)=36得到5x+y=36
4(x+y)-5(x-y)=2得到-x+9y=2
联立解得y=1,x=7

3(x+y)+2(x-y)=36 4(x+y)-5(x-y)=2 (x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)= 2（x+y)-3(x-y)=3 ,4(x+y)+3(x-y)=15 {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 3(x+y)-2(x-y)=11 4(x+y)+3(x-y)=9 （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 4(x-y)-3(x-y)=9 5(x-y)+2(x-y)=11 3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27 先化简再求值(x-y)(x-2y)+(x-2y)(x-3y)-2(x-3y)(x-4y) x=4 y=5 x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 已知2y-x=-3,求[4y(2x-y)-2x(2x-y)]/(2x-y x+y+2(-x-y+1)=3(1-y-x)-4-(y+x-1),x+y=? 3x+3y+2x-2y=36 4x+4y-5x-5y=2 3(x+y)+2(x-y)=36 4(x+y)-5(x-y)=2 解方程组