Answer:
About 5043.58
Step-by-step explanation:
The standard form for an exponential decay after t time is:

Where a is the initial value, r is the rate decay, t is the time that has passed, and d is the amount of time it takes for 1 cycle.
The initial value is 9800. So a = 9800.
The quantity cuts in half. So, r = 1/2.
And it cuts in half every 6 days. For this question, we will convert this to hours. 6 days = 144 hours. So, we can let d = 144, where t will be in hours.
Therefore, our function is:

Where t is the amount of time that has passed, in hours.
Then the quantity left after 138 hours will be:

Answer:
a
Step-by-step explanation:
the solution to the system is at the point of intersection of the linear equations.
the lines intersect at (- 4, 3 )
then solution is (- 4, 3 )
.
Rates:
Ryan: 1 hole per 5 hours
Castel: 1 hole per 6 hours
.
Let x = time if working together
then
x(1/5 + 1/6) = 1
x(6 + 5) = 30
11x = 30
x = 30/11
x = 2.7273 hours
or
x = 2 hours and 44 minutes
x^3 + 64 = 0
Subtract both sides by 64:
x^3 = -64
x = -4