Answer:
S = 4w + 120
Explanation:
Let's use "S" for the total number of songs.
Since the amount is increasing at a steady rate, it is a linear equation, so it has the form of:
y = mx + b
m is the slope (rate of change) and b is the y-intercept (the starting value).
The number of songs starts at 120 and increases by 4 each week, so the equation is:
S = 4x + 120