а по-другому нельзя?примерно так
Sub Zad2()
Dim x As Single, y As Single, i As Integer, n As Integer
Dim s As Single
n = 0
s = 0
y = 5
For x = 1 To 5
If x < y Then
For i = 1 To 20
s = s + (x ^ i) * (y ^ (i + 1))
Cells(9 + n, 3) = s
Next i
End If
If x > y Then
s = (x ^ 2) * (y ^ 2)
Cells(10 + n, 3) = s
End If
If x = y Then
s = (x ^ 2) + (y ^ 2)
Cells(11 + n, 3) = s
End If
y = y - 1
Next x
n = n + 1
Cells(8 + n, 2) = y
Cells(8 + n, 1) = x
Cells(8, 1) = "x="
Cells(8, 2) = "y="
Cells(8, 3) = "s="
End Sub