Answer:
2k
Step-by-step explanation:
3k and -k are both like terms, so you can combine them. Adding opposite signs works in the same way as subtraction, so you can rewrite the expression as 3k-k, which is 2k.
Answer:
11, 17, and 28.
Step-by-step explanation:

Lowest number is 
Median is 
Highest number is 

y = ax^2
If the absolute value of a is <1 the graph is wider than when a = 1
If the absolute value of a is >1 the graph is narrow than when a = 1
The only function that fits that description is
y = 2x^2
the numbers are: 100,500 ; 655,980 ; 324,000 ; 900,378
least to greatest: 100,500 ; 324,000 ; 655,980 ; 900,378