Respuesta :

Answer:

The answer is -3

Step-by-step explanation:

1. Distribute -7z + 21 = 42

2. Subtract  42 - 21 = 21

3. -7z = 21

4. Divide 21 / -7 = -3

5. Answer is -3

So first multiply -7 by (Z- 3)
And you get 42= -7z + 21
Then subtract 21 from both sides of the equation and you get 21= -7z
Then divide -7 from both sides of the equation
And finally you get Z= -3