Hash function is:

$h(key)=key\ mod\ 7$

Insert keys one by one.

$44\ mod\ 7=2$, so $44$ goes to index $2$.

$45\ mod\ 7=3$, so $45$ goes to index $3$.

$79\ mod\ 7=2$, but index $2$ is filled. Using linear probing, index $3$ is also filled, so $79$ goes to index $4$.

$55\ mod\ 7=6$, so $55$ goes to index $6$.

$91\ mod\ 7=0$, so $91$ goes to index $0$.

Now for key $18$:

$18\ mod\ 7=4$

Index $4$ is already filled by $79$.

Using linear probing, next index $5$ is empty.

So, key $18$ is inserted at index $5$.