Question 51822
Total cost of calling x minutes: y
number of minutes called: x
rate per minute is the slope m: $0.25
flat fee without adding minutes is b: $0.75
Substitue these values into y=mx+b and you have:
y=.25x+.75
In order to find out the cost of talking 5 minutes, substitute 5 in for x:
y=.25(5)+.75
y=1.25+.75
y=2.00
It costs $2.00 to talk five minutes.