Answer:
14.4444 miles
Step-by-step explanation:
y=4+0.9x
plug in 17.5 for y
then solve
Answer: $22.68
Step-by-step explanation:
17.50 times 0.08 = 1.40
17.50 + 1.40 = 18.90
Now the tip:
18.90 times .2 = 3.78
18.90 + 3.78 = 22.68
Let's start from what we know.

Note that:

(sign of last term will be + when n is even and - when n is odd).
Sum is finite so we can split it into two sums, first

with only positive trems (squares of even numbers) and second

with negative (squares of odd numbers). So:

And now the proof.
1) n is even.
In this case, both

and

have

terms. For example if n=8 then:

Generally, there will be:

Now, calculate our sum:



So in this case we prove, that:

2) n is odd.
Here,

has more terms than

. For example if n=7 then:

So there is

terms in

,

terms in

and:

Now, we can calculate our sum:




We consider all possible n so we prove that: