.{x/2+y=1 x/2-1/3y=-1 {3m-n=1,3m+2n=16 {3m+2n=2,2m-n=2 {4/5x
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x/2+y=1 ① ④⑤⑥

x/2-1/3y=-1②

①-②得：y+1/3y=2.4y/3=2.4y=6.y=3/2.代入①,x/2+3/2=1,x+3=2, x=-1

x=-1

y=3/2

3m-n=1①,

3m+2n=16②

②-①得：3n=15.n=5.代入①,3m-5=1, 3m=6, m=2.

m=2

n=5

3m+2n=2①,

2m-n=2②

②x2+①得：7m=6...m=6/7.代入②,2x6/7-n=2, 12-7n=14, n=-2/7

m=6/7

n=-2/7

4/5x-3/4y=1①,

4x-3y+1=0②

①x5-②得：-3y/4=6...3y=-24.y=-8,代入②,4x+24+1=0, 4x=-25, x=-25/4.

x=-25/4

y=-8

3y=x-(x-1)/3①,.3y=(2x+1)/3③

3y=(x+2)/6+2②

③-②得：(2x+1)/3-(x+2)/6-2=0,.2(2x+1)-(x+2)-12=0,.4x+2-x-2-12=0, x=4.代入③,

3y=(2x4+1)/3=3,.y=1

x=4

y=1

5x+2y=25,

3x+4y=15

①x2-②得：7x=35,..x=5,代入②,15+4y=15,...4y=0,..y=0.

x=5

y=0

3(x-1)=4(y-4).4y-3x=13①

2(y-1)=5(x+3).2y-5x=17.4y-10x=34②

①-②得：7x=-21, x=-3,代入①,4y+9=13, 4y=4, y=1

x=-3

y=1

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