Answer:
a)
, b) 
Step-by-step explanation:
Overall speeds up river and down river are modelled by following expressions:
Up River

Down River

After some algebraic manipulations, speeds are found:


Multiply the left side by 63....does that help?
The answer is C) negative slope
Answer:
a. d/2 = r; b. 65 miles per hour
Step-by-step explanation:
d = 2r
d/2 = r
130/2 = r
65 = r
Answer:
a. Rafael
b. Jordan
Step-by-step explanation:
Firstly, we should understand that a negative value of elevation indicates that the position is below sea level.
So the person at a higher elevation is the person above the sea level which is Rafael in the case.
Now to the second question, we want to know who is farther from the sea level.
The correct answer is Jordan.
Let’s see the sea level as an origin (0,0) on a cartesian plane and coordinate. We should understand that although sign maybe different, the numbers which are higher in magnitude in either direction shows the farthest from the origin.
So therefore, Jordan is deeper below the sea level than Rafael who is above the sea level.