Hi. i need with math. show work. best gets brainliest.

12a.
        35 + 3c = 45 + 2c     subtract 35 from both sides
                3c = 10 +2c       subtract 2c from both sides
                  c = 10
A 10 minute phone call would cost the same amount of money with both companies.

12b.
          It is better to use Company B when you need to make a longer phone call because the cost per minute is less. For example, an hour long phone call with company A would be $2.15 and the same call with company B would be $1.95.

14.
       The problem with Delia's work is that she put the x with the flat rate instead of the daily charge. The flat rate will only be charged once while the daily fee should be multiplied and charged for every day, x. The correct equation would have been 365 + 125x = 250 + 175x.
        

Cost=time times cost per unit of time
Acost=3m+35
Bcost=2m+45

a. when legnth is same, cost is same, find
3m+33=2m+45
minus 2m
m+35=45
minus 35
m=10
10 minutes

b. b is better since lower rate

14. flat fee doesn't change so it is added at end
125 per day, 125 times x number of days
rentatentcost=125x+365

capital rentals, flat is 250
175 per x days
capidalrentcost=175+250

equal cost, set equal to each other
125x+365=175x+250
error is she multpiplied by the flat fee rather than the rate