Поиск среднего значения функции, при заданном Х - VB

Private Sub Command1_Click()
    Dim x, y As Double, a As Double, b As Double
    Dim sum As Double, i As Integer, c As Integer
     x = Array(0.25, 0.43, 0.7, -0.5, 7)
     a = -1.2
     b = 0.6
     For i = 0 To UBound(x)
          y = a + x(i) ^ 2 / b + x(i)
          sum = sum + y
          c = c + 1
     Next i
     Print sum / c
End Sub