Solution to Linear Equations with Graph

Dim X1 As Double
Dim Y1 As Double
Dim Z1 As Double
Dim X2 As Double
Dim Y2 As Double
Dim Z2 As Double
Dim X As Double
Dim Y As Double
Dim I As Integer
Private Sub cmdSOL_Click()
X1 = txtX1.Text
Y1 = txtY1.Text
Z1 = txtZ1.Text
X2 = txtX2.Text
Y2 = txtY2.Text
Z2 = txtZ2.Text
X = (Y1 * Z2 - Z1 * Y2) / (X2 * Y1 - X1 * Y2)
Y = (Z1 * X2 - X1 * Z2) / (X2 * Y1 - X1 * Y2)
txtX.Text = X
txtY.Text = Y
End Sub

Private Sub Command1_Click()
Picture1.Cls

X1 = txtX1.Text
Y1 = txtY1.Text
Z1 = txtZ1.Text
X2 = txtX2.Text
Y2 = txtY2.Text
Z2 = txtZ2.Text

Picture1.ForeColor = vbBlack
Picture1.DrawWidth = 3
Picture1.FillStyle = vbSolid
Picture1.FillColor = vbRed
Picture1.Scale (-10, 10)-(10, -10)
Picture1.Line (-10, 0)-(10, 0)
Picture1.Line (0, 10)-(0, -10)
For I = -9 To 9
 Picture1.Line (I, -0.3)-(I, 0.3)
 Picture1.Line (-0.3, I)-(0.3, I)
 Picture1.Circle (I, 0), 0.15
 Picture1.Circle (0, I), 0.15
Next I

Picture1.ForeColor = vbBlue
X = -10
Y = (Z1 - X * X1) / Y1
Picture1.CurrentX = X
Picture1.CurrentY = Y
For X = -10 To 10
Y = (Z1 - X * X1) / Y1
Picture1.Line -(X, Y)
Picture1.Circle (X, Y), 0.2
Next X

Picture1.ForeColor = vbGreen
X = -10
Y = (Z2 - X * X2) / Y2
Picture1.CurrentX = X
Picture1.CurrentY = Y
For X = -10 To 10
Y = (Z2 - X * X2) / Y2
Picture1.Line -(X, Y)
Picture1.Circle (X, Y), 0.2
Next X

End Sub

Private Sub Picture1_MouseMove(Button As Integer, Shift As Integer, X As Single, Y As Single)
Picture1.ToolTipText = "( " & Round(X, 1) & "," & Round(Y, 1) & " )"
End Sub