I’m also stuck on this question
<h3>Check the possibilities:</h3><h2>A:</h2>
u(n)=n-1
u(6)=6-1= True
u(10)=10-1≠7 False
<h3>
A is eliminated.</h3>
<h2>
B:</h2>
u(n)=2n-7
u(6)=2(6)-7=12-7=5 True
u(10)=2(10)-7=20-7≠7 False
<h3>
B is eliminated.</h3>
<h2>
C:</h2>
u(n)=0.5n+2
u(6)=0.5(6)+2=3+2=5 True
u(10)=0.5(10)+2=5+2=7 True
<h2>
C is your answer.</h2>
<h3>
Check D although we know it's C:</h3>
u(n)=n/6 +4
u(6)=6/6 +4=1+4=5 True
u(10)=10/6 +4=2.5+4=6.5≠7 False
Answer:

Step-by-step explanation:
So we have:

Remove all the fractions to make things simpler. To do so, we can multiply by the LCM of the denominators.
The denominators are 3 and 7.
The LCM of 3 and 7 is 21. Thus, multiply everything by 21:

Distribute:

Simplify the fractions:

Add 12x to both sides:

Subtract 9 from both sides:

Divide both sides by 26:

Reduce:

And that's our answer :)
I think you'd have to get 41 questions right . But it also depends on the grading scale how many points do you get a question?