Answer: 
<u>Step-by-step explanation:</u>
Given: cos x =
, x is in Quadrant 4
Use Pythagorean Theorem to find sin x:
8² + y² = 17²
y² = 17² - 8²
y² = 289 - 64
y² = 225
y = 15
→ sin x = 
Use the double angle formula to find cos (2x):

It opens downwards so it looks like this “n”. That is because a in the formula is a negative number in this situation
Answer: 0.40 = x
Step-by-step explanation:
3x + 13 = 7x - 15
15 - 13 = 7x - 3x
2 = 5x
2/5 = x
0.40 = x
Answer:
5:00 pm
Step-by-step explanation:
11:00 + 5 is 4.00 so you'd be a 4:40 + 20 minutes, that ranks up another hour so its at 5:00 pm