table 4 . Direct Variation, constant of proportionality =8
Table 5: No. There is not a direct variation, for the growth is not at a constant factor.
1) To state whether there is a direct variation, we need to examine each row to stat how it increases or decreases
2) So for table 4
x  y            
3  24
4   32
5    40
6    48
For this, we can write a linear function y=8x
Yes. Direct Variation. Constant of proportionality 8
Table 5
x  y
185  60
235  100
285  140
335  180
No. There is not a direct variation, for the growth is not at a constant factor.
Table 6
x  y
5  12.5
10  25
15   37.5
20   50
We can set a linear function for that  y=5/2 x
Yes.  Direct Variation. Constant of proportionality  5/2 (2.5)
Table 7
x y
2 4
3  5
4 6
5  7
There is not a direct variation, for the growth is not at a constant factor.