Answer:
The costs of the plan are $0.15 per minute and a monthly fee of $39
Step-by-step explanation:
Let
x ----> the number of minutes used
y ----> is the total cost
step 1
Find the slope of the linear equation
The formula to calculate the slope between two points is equal to
we have the ordered pairs
(100,54) and (660, 138)
substitute
step 2
Find the equation of the line in point slope form
we have
substitute
step 3
Convert to slope intercept form
Isolate the variable y
therefore
The costs of the plan are $0.15 per minute and a monthly fee of $39