Должно быть примерно так: Sub number3()
Dim a As Single, h As Single, x As Single, F As Single
Dim S As String
a = 10
h = 0.2
x = -1
S = " "
'Начало цикла с предусловием
Do While -1 <= x <= 1<br>F = Format((2 * a + x) / (3 * a - x), "FIXED")
S = S + " " + Str(F)
S = a + h + x
Loop
MsgBox "S= " & S, vbInformation, "Значения функции"
End Sub