12000 x 0.40 = 4800
12000 - 4800 = 7200
7200 acres are being logged
hope this helps
Answer:
(a) 
(b) 4 miles
Step-by-step explanation:
Given:
The sequence of run is an arithmetic sequence.
Miles traveled on day 1 = 1 mile
Miles traveled on day 7 = 2 miles
(a).
Explicit formula for an arithmetic sequence is given as:

Here, 
So,

Therefore, the explicit definition of the above sequence is given as:

Where,
is the miles covered on
day.
(b)
In order to find the distance covered by her on day 19, we plug in 19 for n in the above formula. This gives,

Therefore, the number of miles covered by her on day 19 is 4 miles.
-7.5 / -2.5 = 3
------------
So discriminant gives us 3 possibilites connected with result of the equation b^2-4ac. If it is bigger than zero, there are 2 solutions, if answer is exactly 0, then there is one answer and if the number is lower than 0, there are no solutions.
Discriminant of your quadratic equation is (-4)^2-4*1*5=16-20=-4, so there are no solutions.