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: 12
Step-by-step explanation:
3 x 4 = 12
Answer:
ye i dont know but nice computer bro
Step-by-step explanation:
(5 | -2) should be the solution of the equations
So it workt for c)
c)
3*(5) - 5*(-2) = 25
(5) + 5*(-2) = -5