Answer:
Part A) 
Part B) 
Part C) 
Step-by-step explanation:
see the attached figure to better understand the problem
step 1
Find the length side AB (hypotenuse of the right triangle)
Applying the Pythagorean Theorem

substitute the given values



simplify

step 2
Find sin(A)
we know that
In the right triangle ABC
----> by SOH (opposite side divided by the hypotenuse)
substitute the given values

step 3
Find tan(B)
we know that
----> by TOA (opposite side divided by adjacent side)
substitute the values

step 4
Find sec(A)
we know that

----> by CAH
so

substitute the values

simplify

Https://www.dropbox.com/s/teq5uhme9jpwma0/Screenshot%202016-10-18%2008.24.17.png?dl=0
Answer:
1km per minute
Step-by-step explanation:
Given the table in the picture :
The average rate of change over the interval from 8 to 15 minutes will be :
Change in distance / change in time
Change in distance between 8 and 15 minutes :
Distance d1 at 8 minutes t1 = 7km
Distance d2 at 15 minutes t2 = 14km
Average rate of change = (d2 - d1) / (t2 - t1)
Average rate of change = (14 - 7)km / (15 - 8)min
Average rate of change = 7km / 7minutes
Average rate of change = 1km per minute
3a - 4b = 21
check (-2 , -3)
3(-2) -4(-3) =21
-6 +12 = 21
6 does not = 21 so NO
check (0 , 7)
3(0) -4(7) =21
0-28=21
-28 does not equal 21 so NO
check (-3 , -2)
3(-3) -4(-2) =21
-9 +8 = 21
1 does not = 21 so NO
check (7 , 0)
3(7) -4(0) =21
21 = 21
Choice D
Yes it would be 7.1 is greater than 7