Combine like terms:
-12 + 5a - a - 6a + 8a + 8 + 3a

5a - a = 4a
4a - 6a = -2a
-2a + 8a = 6a
6a + 3a = 9a
-12 + 8 = -4
Answer

I think that she could buy 3 tubes of paint because that's $25.50 and that gives you 28.50 for the canvas.
Answer:
10.75
Step-by-step explanation:
To get the average, we always SUM UP all the numbers and divide by the number of numbers.
We do this for "change" row since we want average of "change".
Let's add up all the changes:
11 + 12 + 10 + 10 + 11 + 10 + 11 = 75
How many numbers are there?
There are 7 numbers
Now, the average:
Average = Sum/Number of Numbers
Average = 
The average = 10.75