Answer:
dy/dx at x=6 is 0.334
Step-by-step explanation:
The center difference method requires that the values of the function are given in equal intervals which is the case, and allows one to find the value for x = 6 using those of the function for x = 5.5 and for x = 6.5 as follows:

3 times 5 times 2.5 = $37.5
3 x 5 =15
15 x 2.5 =37.5
37.5 x 2 = 75 for both of them
I don't know if this is right or not, but that's how I would solve it!
Answer: 2.592 x 10^6 seconds
Explanation:
There are 3600s in 1 hr
And 24hrs in 1 day which mean
There are 3600 x 24 = 86400s in 1 day
And one month = 30 days
86400 x 30 = 2, 592, 000s in 1 month
Write in scientific notation:
2, 592, 000 = 2.592 x 10^6
You have to make a proportion:
12+x/8=8/x
Then cross multiply to solve for x