Respuesta :

Answer:

1 is correct answer

Step-by-step explanation:

[tex]21 = 3(x + 6) \\ 21 = 3x + 18 \\ 21 - 18 = 3x \\ 3 = 3x \\ x = \frac{3}{3} \\ x = 1[/tex]

hope it helped you:)