Kelly should get back $6.72.
To get this answer, start by adding 16.79 and 28.49. The answer you should get is 45.28. Next, subtract 45.28 from 50 and your total should be 6.72. Hope this helped!
Ok, so you have your equation, 5·x+5-(5x+25).
First, do the prathases, so you have, 5x+5-5x-25.(5·x also means 5x)
Now, you need to combine like terms, and through that the xs cancel out, so you are left with -20 as you answer.