EXPLANATION
Given the function 2x+12 and the variable x that represents the number of movies.
Kayla has $10.
In order to rent more movies, we can apply the following algebraic expression to get the solution:
If she needs to rent 7 movies, she would has:
2*7+12 = 2+12 = 14+12 = 26 dollars
So, she need 26 dollars - 10 dollars(Available) = $16.00
Hence, Kayla needs $16 more dollars to rent 7 movies.