如何用vb求解三元一次方程组？

初学vb的算法，不会了。求方程组
10*x1-2*x2-x3=3,
-2*x1+10*x2-x3=15
-x1-2*x2+5*x3=10要求误差小于0.0005，初值用0,0,0带入。最好用雅克比迭代法。
自己编的
Private Sub Command1_Click()
Dim x1#, x2#, x3#, x12#, x22#, x32#
x1 = 0: x2 = 0: x3 = 0
Do Until Abs(x12 - x1) <= 0.0005 And Abs(x22 - x2) <= 0.0005 And Abs(x32 - x3) <= 0.0005
x12 = 0.2 * x2 + 0.1 * x3 + 3
x22 = 0.2 * x1 + 0.1 * x3 + 1.5
x32 = 0.2 * x1 + 0.4 * x2 + 0.2
x1 = x12
x2 = x22
x3 = x32
Loop
Print x12; x22; x32
End Sub
这样无法做出来，菜鸟啊，求帮助。

有必要嘛？考试考过就行。