The answer to number 13 is141
Complementary angles total 90°
One angle is 6 + .5x, so both angles added together is

First, we add one angle to the other, and set it to 90°. Then, we simplify the equation. Then, we subtract 6 from both sides. Then we divide both sides by 1.5
The first angle is 56°
The second angle is 90 - 56, which is 34°
Answer:
-20 Feet.
The dolphin went below its initial starting point, Zero
Attached the solution and work. Not sure about number 3. You might have to check that one.
Answer:
I am thinking it is 112° or 136°
Let me know which one. Hope it helps though =)