Answer:
21.9
Step-by-step explanation:
circumference = pi x diameter
3.14 x 7 = 21.9
Combining those like terms would end as 3n.
Explanation: The end of a subtraction equation is basically just the negative number, except you add it to the other part.
For example, 2n is really -2n, and you just add -2n to 5n (which is positive,) and you get 3n.
Its 9 gigabytes because there is 100 megabytes in a gigabyte.
I hope this helps.