Answer:
Part 3)


Part 4) 
Step-by-step explanation:
Part 3)
<em>step 1</em>
Find the value of x
In the right triangle of the figure we know that
The cosine of angle of 30 degrees is equal to the adjacent side to angle of 30 degrees divide by the hypotenuse
so

and remember that

substitute

Simplify

<em>step 2</em>
Find the value of y
In the right triangle of the figure we know that
The sine of angle of 30 degrees is equal to the opposite side to angle of 30 degrees divide by the hypotenuse
so

and remember that

substitute


Part 4) Find the value of x
Applying the Pythagoras Theorem

Simplify

Answer:
(a)

(b)

(c)

Step-by-step explanation:
(a)
Simply evaluate (a+h) in the function:

(b)
Evaluate (a) in the function:

Using the previous answers lets calculate f(a+h)-f(a)

(c) To find the rate of change of f(a+1) when a=7 we need to calculate its derivate at that point:

If there are 10 reams, and each ream is 32 ounces, then there is 320 ounces total im the case! Then, if you know that there are 16 ounces in a pound, then you can do 320/16, and get a total of 20 pounds in the case!
Hope this helped!