If s represents the number of songs Kim downloads, her expenses for a month must satisfy the inequality
5.00 + 0.58·s ≤ 13.00
To solve this, subtract 5.00 to get the s-term by itself, then divide by the coefficient of s.
0.58·s ≤ 8.00
s ≤ 8.00/0.58 ≈ 13.79
The number of songs must be an integer, so we conclude Kim can download 13 songs, but not 14 songs.
Kim can download 13 songs without exceeding her budget.