Answer:
(a) 
(b) 
(c) 
Step-by-step explanation:
Given
Variation: Direct
Represent ear pressure with p and depth with d.
So, we have:

when 
Solving (a): Write a variation
We have:

Write as an equation

Where: k is the constant of variation
when 
So, we have:

Make k the subject


Substitute 0.43 for k in 

Solving (b): Pressure at 50 feet
Substitute 50 for d in 


The pressure is 21.5 pounds per square
Solving (c): The safe depth
The safe depth stops at a pressure of 65psi.
Substitute 65 for p in 

Make d the subject


-- approximated
<em>The safe distance for an amateur is 151.163ft</em>
-5 =(8m+12)/4
multiply each side by 4
-20 = 8m + 12
subtract each side by 12
-32 = 8m
Divide each side by 8
-4 = m
The answer is B
<span>-6(24x+18)=43(5+5x)
-144x - 108 = 215 +215x
-108 = 215 + 359x
-323 = 359x
-323/359 = x
If you would like me to explain more details i will!</span>