Answer:

Step-by-step explanation:

Answer:
a
Step-by-step explanation:
to be a function, every x has to have exactly one y, so there can't be the same number x twice wirh different y's
Easily, take the square root of the number in the right side to find the radius

is the answer
Answer:
x=21−7y?
Step-by-step explanation:
I don't really know what else to do