y - 3x = 7
can be written as
y = 3x + 7
For every value of x there is a unique value of y. For example when x = 0 y = 3(0) + 7 = 7
Yes it is a function.
In particular it is a one-to-one function.
No they are have a great day
Answer: 
Step-by-step explanation:
All radii of a circle are congruent, so by the base angles theorem
Also, angles x and y are inscribed in the same arc, and they are thus congruent, meaning x = 65.
The radius of a circle is
always half of the diameter of the circle. In this case, the diameter is

, meaning that when we halve

, we will get our radius. Therefore, the radius of the circle is

. Hope this has helped you understand and have a great day!