Please help i don't understand

Mp model with mathematics explain how the number of text messages dario sent and the cost form an arithmetic sequence.then write an expression to find dario's text messaging bill if he sends n text messages over 250.

Saline iv fluid bags cost $64.20 for 24, 1000 ml bags from one supplier. another supplier sells 500 ml bags for $2 each. the hospital uses about 10,000, 1000 ml bags each month. nurses report that about half of the bags are more than half full when they are discarded. if you are going to use only one supplier, which would you choose and how much would you save with that choice? show calculator try it! if you buy 1000 ml bags, how many do you need to buy each month? type your answer in the space provided and click on the check answer button.

Which of the following shows the graph of y=2e^x?