(Use Solving Systems by Graphing to find a solution for this question) One cellphone provider DU charges AED10 per month plus an activation fee of AED20. A second cellphone provider ETISALAT charges AED11 per month plus an activation fee of AED15. For what number of months is the cost of either cellphone provider the same?

5 months

Step-by-step explanation:

One cellphone provider charges AED10 per month plus an activation fee of AED20.

If I used the services of this cellphone provider for x months, total charges for the services,

y = 10x + 20 (1)

Similarly, charges for the second cellphone provider for x months of uses will be,

y = 11x + 15 (2)

Input-output table for equation (1)

x      1           2            3            4            5

y     30        40         50          60          70

Input output table for equation (2)

x      1           2            3            4            5

y     26        37          48          59         70

From these tables, we find (5, 70) is a common point for both.

It reveals that after the uses of 5 months charges for both the cellphone providers will be same (y = $70)