Answer:
Step-by-step explanation:
The equation Thomas wrote is:
...equation 1
Let us subtract 3x from both sides to get:
We now multiply through by 2 to get:
....equation 2
We can see that equation one and two are equivalent and hence have the same solution.
Therefore Sandra's equation is 
12/15,7/25,3/7,3/5 should be correct because this is what my teacher taught me in fourth grade.
Mean=8.1 (add all numbers and divide by how many there r)
Median=9.25 (place all numbers in a chronological line and find the middle value)
Mode=9.2 (value that appears the most)
Range=10.5 (10.5-0)