解几道二元一次方程{9x-5y=1 {2002x-2003y=2004 {18(x-3)+5(3/2+y)=56x-7y=2 2001x-2002y=2003 6(3/2+y)-7(x-3)=6{3x-2y=11 2x+3y=16
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![解几道二元一次方程{9x-5y=1 {2002x-2003y=2004 {18(x-3)+5(3/2+y)=56x-7y=2 2001x-2002y=2003 6(3/2+y)-7(x-3)=6{3x-2y=11 2x+3y=16](/uploads/image/z/11436020-44-0.jpg?t=%E8%A7%A3%E5%87%A0%E9%81%93%E4%BA%8C%E5%85%83%E4%B8%80%E6%AC%A1%E6%96%B9%E7%A8%8B%7B9x-5y%3D1+%7B2002x-2003y%3D2004+%7B18%28x-3%29%2B5%283%2F2%2By%29%3D56x-7y%3D2+2001x-2002y%3D2003+6%283%2F2%2By%29-7%28x-3%29%3D6%7B3x-2y%3D11+2x%2B3y%3D16)
解几道二元一次方程{9x-5y=1 {2002x-2003y=2004 {18(x-3)+5(3/2+y)=56x-7y=2 2001x-2002y=2003 6(3/2+y)-7(x-3)=6{3x-2y=11 2x+3y=16
解几道二元一次方程
{9x-5y=1 {2002x-2003y=2004 {18(x-3)+5(3/2+y)=5
6x-7y=2 2001x-2002y=2003 6(3/2+y)-7(x-3)=6
{3x-2y=11
2x+3y=16
解几道二元一次方程{9x-5y=1 {2002x-2003y=2004 {18(x-3)+5(3/2+y)=56x-7y=2 2001x-2002y=2003 6(3/2+y)-7(x-3)=6{3x-2y=11 2x+3y=16
1.
{9x-5y=1
6x-7y=2
{9x-5y=1
9x-(21/2)y=3
9x-(21/2)y-(9x-5y)=3-1
-(11/2)y=2
y=-(4/11)
x=-(1/11)
2.
{3x-2y=11
2x+3y=16
{6x-4y=22
6x+9y=48
(6x+9y)-(6x-4y)=48-22
6x+9y-6x+4y=26
13y=26
y=2
x=5
3.
{2002x-2003y=2004
2001x-2002y=2003
(2002x-2003y)-(2001x-2002y)=2004-2003
2002x-2003y-2001x+2002y=1
x-y=1
2001(x-y)-y=2003
-y=2003-2001
y=-2
x=-1
4.
{18(x-3)+5(3/2+y)=5
6(3/2+y)-7(x-3)=6
{108(x-3)+30(2/3+y)=30
30(3/2+y)-35(x-3)=30
[108(x-3)+30(3/2+y)]-[30(3/2+y)-35(x-3)]=30-30
108(x-3)+30(3/2+y)-30(3/2+y)-35(x-3)=0
143(x-3)=0
143x-429=0
x=3
y=-(1/2)