So firstly, we have to find the LCD, or lowest common denominator, of 9 and 7. To do this, list the multiples of 9 and 7 and the lowest multiple they share is going to be your LCD. In this case, the LCD of 9 and 7 is 63. Multiply x^2/9 by 7/7 and 2y/7 by 9/9:

Next, add the numerators together, and your answer will be: 
Answer:
7
Step-by-step explanation:
(1 + x) (13) = 13+6.5
13x + 13 = 19.5
13x = 6.5
x = 0.5
The item was marked up by 50%
1 2/3 is the same as 5/3, so the reciprocal is 3/5