Answer:
3x was subtracted from the left side, but 3x was subtracted from the right side. The Subtract Property of Equality states that you can subtract the same number from each side and the equation will remain true. But 3x and 3 are not the same number (unless x is 1).
x = -8/5
Step-by-step explanation:
Step 1: Simplify both sides of the equation.
Step 2: Subtract 12 from both sides.
Step 3: Divide both sides by 10.