Answer:

Step-by-step explanation:
120 degrees is one third of the whole circle, or 
Answer:
6 ≤ x < ∞
Step-by-step explanation:
The value of x cannot be less than 6 because that would make the term in the square root part negative. There is no real square root of a negative vale.
It could be x > 21 im not sure
You just flip each of the numbers spots - the x and y
Answer: D (5/2, -17/4)
Step-by-step explanation: Using elimination your goal is to get rid or 1 variable so you can solve for the one that's left. By adding the -2y and 2y you will get 0. You will also add the 3x+x (4x) and -1+11 (10). You have now gotten rid of the y and have 4x=10. By dividing each side by 4 we now know x =2.5. D is the only possible solution with x=2.5 (5/2) but to solve for y you plug 2.5 in to an equation as x so) x-2y=11
2.5-2y=11
-2y=8.5 Answer D (5/2,-17/4) y=-17/4 (4.25)