Answer: 20
Step-by-step explanation:
You find the mean by adding up all the numbers in a data set, then dividing by the number added.
18 + 15 + 22 + 18 + 25 + 19 + 23 + 20 = 160
We added 8 numbers together, so we divide 160 by 8
160/8 = 20
1. Fifteen thousand six hundred and thirty eight
Any point with coordinates (x, y) reflected across the y-axis is going to have the opposite x value that it did before.
You should be able to find the coordinates yourself for part a. (you didn't provide the original ones so I can't help you there)
Here is the "rule" for a reflection across the y-axis:

And when we go 1 unit to the right and 2 down, that's the same as

Combining those into one rule is pretty simple, Use our result for the first in the second and we would get

, so the rule is

.
Part A is asking for the coordinates after the reflection (x, y) ⇒ (-x, y).
Part C is asking for the coordinates after the full translation ⇒ (-x+1, y-2)
2(x-7)/3=-2
3*2(x-7)/2*3=-2*3/2
x-7=-2*3/2
x-7=3*-1
x+(7-7)-7-3
x=7-3
x=4
23. -7
24. greater. For example, when u subtract -5 from 10, the answer is 15, which is greater than 10
25. the pattern each term is subtracted 5 from it's previous term