K would be 13 I hope his helps
Answer:
1.28/7. 2.-17/7. 3.-11/-3. 4.not sure. 5. cant remeber rest
<h3><u>Answer</u>:- </h3>

<h3><u>Solution:-</u></h3>
<u>Given </u><u>that </u><u>:</u><u>-</u>
- job last for h hours
- Cost of job lasting more than 1 hour = $30
- Cost for the first hour = $75
Remaining hours for which the job will last after first hour= (h-1)
<u>Therefore</u>,
Cost for subsequent hours = 30×(h-1)
= 30(h-1)
Total Cost for job = Cost for 1st hour + Cost for subsequent hours

Consider expression
First, you can factor it:

Since x is integer number, then you can see that x-1 is previous integer number (x-1 is 1 unit smaller than x).
Therefore, x-1 and x are two consecutive integers. When you have two consecutive integers, one of them is always even and one is always odd. Multiplying even integer number by odd integer number you always get even integer number.
Thus,
is always even.