hi! so i tried to solve this one for you, let me know if it is right..! have a great day
Answer:
This is an improper fraction so we need to make it a mix fraction.
Step-by-step explanation:
21/10 = 10/10+10/10+1/10
10/10=1
So your final answer will be 
Hello,
Let's suppose f(x)=3x+7
f(a-1)=3(a-1)+7=3a-3+7=3x+4
Answer B with a sign "++++++++++++++++++++++++++++"