Sub CHOBSB(A(), N, D(), B())
    For I = 1 To N
        Sum = B(I)
        For J = 1 To I - 1
            Sum = Sum - A(I, J) * B(J)
        Next J
        B(I) = Sum
    Next I
    For I = N To 1 Step -1
        If D(I) = 0# Then
            Print "  Singular Matrix"
            Exit Sub
        Else
            Sum = B(I) / D(I)
        End If
        For J = I + 1 To N
            Sum = Sum - A(J, I) * B(J)
        Next J
        B(I) = Sum
    Next I
End Sub