Answer:

Explanation:
So, we know that Ava already has $100. This is our constant. 
We also know that she saves $6 per week w. In other words, the total money she has after w weeks is: 

This is our expression. 100 represents the $100 she already has and the 6w represents the amount of money she will have saved after w weeks. 
To find out how much total money Ava would have after 9 weeks, substitute 9 for w. Thus: 

Multiply: 

Add: 

So, after 9 weeks, Ava would have $154. 
And we're done!