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.
Answer:
Step-by-step explanation:
a^2 - 5bc - 1
a = 7
b = 3
c = 2
7^2 - 5*3*2 - 1
49 - 30 - 1
18
Answer:
rational
Step-by-step explanation:
irrational is something like pi or square root of 3, -27 is a simple number.