Remark
Average in this case does not mean you take (s1 + s2)/2. What average speed means is Total Distance / Total Time.
Formula
Average speed(s) = Total Distance / Total Time
Givens
Total Distance = 252 + 30 = 282 miles
Total Time = 5 hours.
Substitute and Solve
Average speed = 282 / 5
Average speed = 56.4 miles / hour <<<<< Answer.
The other facts are not used.
So this is trig, and when it comes to right (90°) triangles, it's imperative that you know:
SOH-CAH-TOA
Sine (x) = Opposite/Hypotenuse
Cosine (x) = Adjacent/Hypotenuse
Tangent (x) = Opposite/Adjacent
*hypotenuse is always the largest side, and the one opposite the 90° angle in right triangles
therefore we'll use SOH, because the opposite of x (O) and the hypotenuse (H) are given:
Sine (x) = Opposite/Hypotenuse
Sine (x) = 32/58 = 16/29 = 0.552
Sine (x) = 0.552
now we use something called arc-sine, or

it's basically a fancy function of most advanced calculators, so we'll plug it in as:

x = 33.49° --> answer B) is correct
Answer:
For D. X= 3, or 0 but probably not 0
For the 2nd picture you sent, x= -2, or -3
Step-by-step explanation:
So for D. you want to make sure you only have 1 Variable, and since we know y=x squared + 7x+5, we subsitute y for what it is equal to.
Then we refine the question, which takes it out to
x squared-3x+5=5 (because the 7x-10x = 3x)
We subtract 5 from both sides which leaves us with x Squared - 3x= 0
Which we then solve with the Quadratic formula. and we separate the solutions to get the different answers for 3, and 0