plug in values for L and solve for w
when L = 1
1=30+0.5w
subtract 30
-29=.5w
divide by .5
w=-14.5
when L=2
2=30+.5w
-28=.5w
w=-14
When L=3
3=30+.5w
-27=.5w
w=-13.5
so your table looks like this:
L W
-------- ------
-14.5 1
-14 2
-13.5 3
-13 4
-12.5 5