Answer:
x = 4
Step-by-step explanation:
We can find the answer to this by solving the equation:
3x - 4 = 8
3x - 4 + 4 = 8 + 4
3x = 12
In this case, 7 is being added to the odometer which already reads 78. If you add 7 to 78, you get 85. Meaning y = 85!
(rounded)