Answer:
We can use the information given to form two equations, which can be used to find the values of c and d in the equation y = c + d(x-1).
From the first month of service, we know that the cost is $75.45, so when x = 1, y = 75.45. Therefore, we have the equation y = c + d(x-1), which can be rewritten as 75.45 = c + d(1-1) or simply 75.45 = c.
Now we can use the information from the second and third months to form another equation. When x = 2, the total charges are $95.36, which is $75.45 plus the cost of the second month of service. Similarly, when x = 3, the total charges are $115.27, which is $75.45 plus the cost of the second and third months of service. We can express these relationships as:
95.36 = c + d(2-1) or 95.36 = c + d
115.27 = c + d(3-1) or 115.27 = c + 2d
Now we have two equations with two unknowns (c and d), which we can solve using algebraic methods. First, we can use the equation 75.45 = c to substitute c in the other two equations:
95.36 = 75.45 + d or d = (95.36 - 75.45) / 1 = 19.91
115.27 = 75.45 + 2d or d = (115.27 - 75.45) / 2 = 19.91
We get the same value of d from both equations, which means it is consistent with the given data. Now we can substitute d = 19.91 and c = 75.45 in the equation y = c + d(x-1) to get the final form:
y = 75.45 + 19.91(x-1)
This equation represents the total charges after x months of service for the Call Me Maybe cell phone provider.