Respuesta :

1. Expand

- 3 - 4m = 28m - 28 - 7m

2. Simplify 28m - 28 - 7m to 21m - 28

- 3 - 4m = 21m - 28

3. Add 4m to both sides

- 3 = 21m - 28 + 4m

4. Simplify 21m - 28 + 4m to 25m - 28

-3 = 25m - 28

5. Add 28 to both sides

- 3 + 28 = 25m

6. Simplify - 3 + 28 to 25

25 = 25m

7. Divide both sides by 25

1 = m

8. Switch sides

m = 1