99我,help

3x+2y=-1---(1)
2x+3y=6---(2)
From (1),y=-(3x+1)/2---(3)
Sub (3) into (2):
2x+3[-(3x+1)/2]=6
4x-3(3x+1)=12
4x-9x-3=12
-5x=15
x=-3---(4)
Sub (4) into (3):
y=-(3x+1)/2
=-[3(-3)+1]/2
=8/2
=4
Therefore x=-3,y=4

{3x+2y=-1----------(1)
{2x+3y=6-----------(2)
(1)*2 6x+4y=-2-----(3)
(2)*3 6x+9y=18------(4)
(4)-(3) 5y=20
y=4

把y=4代入公式(1):
3x+8=-1
3x=-9
x=-3

2007-03-06 09:21:13 補充：
so x=-3,y=4

2007-03-06 14:02:36 補充：
我用消元法

2007-03-06 17:25:03 補充：
If use 代入法：從(1)=2y=-1-3x y=-(1-3x)/2把（3）代(2):2x+ 3(-1-3x)/2=62x+3/2(-1-3x)=62x-3/2-9/2x-=612x-9-27x=3615x=-45x=-3把x=-3代入:y=[-1-3(-3)]/2 =[-1+9]/2 =4so I think用消元法恰當．