Edward solved the equation 4x + 1 = 5x + (−5) using these steps.

1. Add 4 negative x-tiles to both sides.

2. Add 5 negative unit tiles to both sides.

3. Solution x = −4.

What was Edward’s mistake?
In step 1, he had to add 4 positive x-tiles.
In step 2, he had to add 5 positive unit tiles.
In step 3, the solution should be x = 4.
Edward did not make a mistake.