Answer:
prett sure it's b
Step-by-step explanation:
1.
3x + 3 = 21
3x = 21-3
3x = 18
x = 18/3
Therefore,
x = 6
So option ( B) is the correct one.
2.

Therefore option (B) is the correct one here too.
It's 12 because if you divide 6 by 0.5 you should get 12, so basically use the opposite operation.
Hope that helps!