Answer:
91 ft ≤ (7 ft)n or n ≤ 13
Explanation:
total amount of edging is
e(n) ≤ 4 ft + (7 ft)n 
This inequality relates the total length of edging to the number of 7 ft rolls needed.
If Natalia needs 95 ft of edging, we write e(n) ≤ 4 ft + (7 ft)n as
95 ft ≤ 4 ft + (7 ft)n 
which simplifies to 
91 ft ≤ (7 ft)n or n ≤ 13
Natalia must purchase 13 rolls. This, combined with the initial 4 ft of edging, will be just the right amount of edging to complete the job.