The property displayed here is the distributive property.
If you have a variable or unknown number inside or outside of parentheses, you can distribute it to each term and add the terms together, and it will remain true.
Example:
4(x + 5)
After distributing, it'll look like this:
4x + 20
Answer: It will one year (or 12 months) before Michael is able to ride the roller coaster.
Step-by-step explanation: Because he grows a half inch every month, this means that It takes him two months to grow one full inch. Because he has to grow six inches, you just multiply 2 by 6 to get 12 months or one year.
21 is the opposite of -21