The slope, or monthly cost, can be found by finding the rate of change between any two points on the table.
For example, to find the slope between month 1 and month 2, we can use the formula:
slope = (y2 - y1) / (x2 - x1)
Using the values from the table:
x1 = 1 (month 1)
y1 = 74 (cost in month 1)
x2 = 2 (month 2)
y2 = 99 (cost in month 2)
slope = (99 - 74) / (2 - 1)
slope = 25 / 1
slope = 25
Therefore, the slope, or monthly cost, is $25.