All the steps arranged in the attachment!
Answer:

Step-by-step explanation:
Let x = number of books that Hannah donated
We know that the number of students is 150 and the total number of books is represented by b, we can write that as:
Average number of books donated by each student = 
Now we know that Hannah donated 3 times as much as the average. We can write that as:

Answer:
8.1 g/cm
Step-by-step explanation:
Answer:
6s⁹t³
Step-by-step explanation:
6s⁵t ₓ s⁴t² =
= 6ₓs⁵⁺⁴t¹⁺²
= 6s⁹t³
Answer:
If Q=2.1(R)+5, then it would be 2.1(5)+5=15.5 ?
Step-by-step explanation: