Answer:
156 minutes
Step-by-step explanation:
So we need to create an equation to represent how Frank's phone company bills him
- I will denote "y" as the total for his bill
- I will denote "x" as the number of minutes Frank uses
So the phone company charges an $8 monthly fee, so this value remains constant and will be our "y-intercept"
They then charge $0.06 for every minute he talks, this will be our "slope"
Combining everything into an equation, we have: y = 0.06x + 8
Now since we were given Franks phone bill total and want to figure out how many minutes he used, we just need to solve the equation for x and plug in our known y value
- y = 0.06x + 8 → y - 8 = 0.06x →
- Then plugging in our y value we get
Frank used up a total of 156 minutes