Answer:
Angle ABC,
Step-by-step explanation:
Please give more detail to your question, this doesn't help at all...
A little more info please?
Answer:
(2,√21)
Step-by-step explanation:
The circle centered at the origin has equation:

Any point that satisfies this equation lie on this circle.
When x=2, we substitute and solve for y.

Take square root to get:

Therefore (2,-√21) and (2,√21) are on this circle.
From the options, (2,√21) is the correct answer
Function means no x value repepetes with a differnt y value
(x,y)
first numbers never repeat
first one, the x values repeat
2nd, x values rpeat
3rd, no repeat
4th, -3 repeats
answer is 3rd option