Answer:
3.81 = 3 81/100
Step-by-step explanation:
This can’t be simplified so it stays as 3 
Answer:
i dont know but can you pick me brainiest
Step-by-step explanation:
That's an expression, so the only thing you can do is simplify it, but that already looks simplified.

which follows from the usual change of coordinates via

and Jacobian determinant

Swap the order, so that the integral is

and now let

, so that

. Now, you have
1. 4/7 2. 1/2 3. 28/105 4. 20 or 20/1
5. 12 or 12/1 6. 9 or 9/1 7. 33/30 or 1 3/30
8. 16/60 or 4/15 9. 15/20 or 3/4
10. 10/24 or 5/12 11. 4 19/24
12. 68/45 or 1 23/45 13. 3/4 of time
14. 1/8 (not 100% sure)