the equation for the line is:
y = -2( x + 1 )
This is an exponential growth problem. Exponential growth can be expressed mathematically in the following way:

.
Parameter a presents initial amount.
Parameter r is percentage increase.
Parameter t is time.
An equation that would describe given problem is:

t is the time in years.
I attached the graph of this function.
Answer:
The speed in still water is 5 miles per hour.
Step-by-step explanation:
distance with current = 90 miles
distance against current = 10 miles
speed in still water = s
speed of current = 4 mph
speed with current = s + 4
speed against current = s - 4
time = t
speed = distance/time
distance = speed * time
With current:
90 = (s + 4) * t
Against the current:
10 = (s - 4) * t
We have a system of equations:
90 = (s + 4) * t
10 = (s - 4) * t
90 = ts + 4t
10 = ts - 4t
Subtract the second equation from the first equation.
80 = 8t
10 = t
t = 10
10 = t(s - 4)
10 = 10(s - 4)
1 = s - 4
s = 5
Answer: The speed in still water is 5 miles per hour.
Answer:
he can run 5 meters in 1 min
Step-by-step explanation:
S = d/t
S=100m/20s
S=5m/s