2. bella's cell phone costs $18 per month plus $0.15 for every minute she uses the phone. last month her bill was $29.25. for how many minutes did she use her phone last month?

Hello! So in order to solve this problem, it's best to start off making an equation.    $18 + $.15x = $29.25  

In this equation x represents the number of minutes she used. So now, we just have to solve for x.

First subtract $18 from both sides. Your new equation will be $.15x = $11.25. Then divide both sides by $.15 to get x by itself. $11.25/$.15 = 75.

So we can conclude that Bella spoke on the phone for 75 minutes this last month. Hope this helps!