Step-by-step explanation:
You said the other one would be the last haha just kidding I'm glad to help.
16. 
First, get rid of that parenthesis.

Now multiply both sides by 2 so that you can isolate k


19. 
This is a pretty easy one. If you didn't know, 121/11 is actually 11 :)

Simply multiply by 3 to isolate r :)


Your answer would be D.
Make this the brainliest answer if it helped!
10 because 7 x 3 = 21 and 7 + 3 = 10 so your answer is 10