Answer:

Step-by-step explanation:
Given:
The average cost of a computer in the year 2000 is given as:

The average cost of a computer in the year 2008 is given as:

Now, the difference in average cost between the years 2008 and 2000 can be calculated by subtracting the average cost in 2000 from the average cost in 2008.
Framing in equation form, we get:
Difference in average cost (ΔC) is given as:

Therefore, the difference in the costs for a computer between 2008 and 2000 is 
Answer:69
Step-by-step explanation:
Answer: perpendicular
Step-by-step explanation:
If you see the below statements among the choices, then you can select these as the answers:
a.) 39 + 2k = 69
2k = 69 - 39
2k/2 = 30/2
k = 15
b.) 39 + 2k = 69
39 + 2(15) = 69
39 + 30 = 69
69 = 69