Answer:
1 3/4
Step-by-step explanation:
5 1/4 / 3 is equal to 1 and 3/4
You can eliminate 81 because we know 
The dot is on approximately 9.32 (my estimate) so I would square that number:
(9.32)² = 86.8624 so if you round this you get 87
Answer:
50,75,and 100 there's supposed to be a 20 too but it's not there but oh well
Take the root of both sides, and solve.
x = 2i sqrt 2, -2i sqrt 2.