To solve for x in the first equation:

8/9 = 9/13

Cross multiply to get:

8 13 = 9 9
104 = 81

This is not a valid equation, so there is no solution for x in this case.

To solve for x in the second equation:

7 1/5 / x = 9/10

Convert the mixed number to an improper fraction:

36/5 / x = 9/10

To solve for x, multiply both sides by x:

(36/5) = (9/10) * x
(36/5) = 9x/10

Now, cross multiply to solve for x:

10 36 = 9 5x
360 = 45x
x = 8

Therefore, the solution for x in the second equation is x = 8.