Here are the answers:
1) C
2) A
3) D
4) B
We know that
Mean and median both try to measure the central tendency in a data set.The mean is commonly used, but sometimes the median is preferred.
Mode is the element which occurs the most times in the set
therefore
the answer is the option
Both the mean and median are appropriate measures of center.
Answer: 
Step-by-step explanation:
See attached image, it's direct formula substitution.
3. 5mn ( 2m + 6n + 1 )
4. 4a^3b^2c ( 18a^2b - 8c )
5. (X-15)(X+15)
6. -4(y-4.5)(y+4.5)
8. 2X(X-10)(X+10)
i am not sure if no. 8 is right
7/7.42 = $0.94
Hope this helped :)