If you would like to know how many pages can Henry write in 8 hours, you can calculate this using the following steps:
5 1/4 = 21/4 pages ... 3 hours
x pages = ? ... 8 hours
21/4 * 8 = 3 * x
21 * 2 = 3 * x
3 * x = 42
x = 42 / 3
x = 14 pages
Henry can write 14 pages of his novel in 8 hours.
7x. Try to ignore the X's for a second and think of the problem as -12+5 (aka 5-12). The answer to that is 7. now add the x back again to get: 7x
Add the 3 item totals, then divide that number by 100, then, take that number and multiply by 9 (this gets the tax total). then you are going to want to add the total of the 3 items, and the tax amount, and you have your answer. do this with all the peoples items :)