Answer: 15
Step-by-step explanation: anything in those two straight lines is automatically positive
I think you meant "y = 4 arccot (x)."
This is equivalent to:
y
---- = arccot x
4
and so cot (y/4) = x
Since we are finding the unit rate of the cost per comic, we will need to divide $5 by 20 comics which you will get 0.25 cents and divide $7.50 by 30 comics which you will also get 0.25 cents.Therefore, the unit rate and constant of proportionality is 0.25 cents.
Answer: Infinite solutions.
Step-by-step explanation:

Plug the value of y into the second equation.

Add 12 on both sides.

Add 4x on both sides.


Answer:
140 minutes
Step-by-step explanation:
After 28 mins you've gone 4 miles, assuming this rate is constant and you dont slow down or speed up, in order to get to 20 miles you will have run 5x as much (20/4 = 5), thus 5x the amount of time (28x5).
20/4 = 5
5x28 = 140