Answer:
1.

2.

Explanation:
1.
- The sum of 3 and 9 entails the addition of those two numbers, and then dividing their sum by a number (represented by x).
2.
- 3 decreased by the quotient of 9 and a number means that you divide 9 and x, and subtract those from 3. That is why 3 must be in front of
.
Hope this helps :) Let me know if you have any questions.