The first two is wrong, the last two is one of the right ones, I think it’s c
Answer:

Step-by-step explanation:
See attached file for complete work.
Complete Question:
Femi's last 5 bowling scores were 68, 75, 72, 90, and 80. What was Femi's mean score?
Answer:
Step-by-step explanation:
Given
Scores: 68, 75, 72, 90, and 80
Required
Determine the mean
The mean (M) of a data is calculated as thus:

Where
n = number of data.
In this case,
n = 5
and
= sum of data
So, the formula becomes



<em>Hence, the mean is 77</em>
Answer:
Step-by-step explanation:
54
True
Like terms must have the same exponents and variables
Hope this helps ;)