Me!
one cell phone plan charges $17.50 per month plus $0.17 per minute used. a second cell phone plan charges $32 per month plus $0.07 per minute used. write and solve an equation to find the number of minutes you must talk to have the same cost for both calling plans.

In constructing the equation, you need to know the following:

1. What don't we know? How many minutes you must talk to have the same cost for both calling plans. So, let x be the number of minutes.
2. What do we know? Plan 1 charges $17.50 per month plus $0.17 per minute used and Plan 2 charges $32 per month plus $0.07 per minute used.

So the equation must look like this: 17.50 + .17x = 32 + 0.07x

Solving the equation:

1. Multiply both sides by 100
(100) 17.5 + .17x = 32 + 0.07x (100)
1750 + 17x = 3200 + 7x

2. Subtract 1750 from both sides
1750 + 17x - 1750 = 3200 + 7x - 1750
17x = 7x +1450

3. Subtract 7x from both sudes
17x - 7x = 7x + 1450 - 7x
10x = 1450

4. Divide both sides by 100
10x / 10 = 1450/10

x= 145 minutes

145 minutes is the number of minutes you must talk to have the same cost for both calling plans.

Ithink the answer is d.