Answer:
When the scale factor between two circles is “x” the scale factor between the radius is also “x” and the scale factor of the area is “x^2"
this is only one possible answer. For example, instead of radius, you could have put diameter or circumference.
X=3 is a vertical line . The question is "Is this line a vertical asymptotefor the function f(x)?". Vertical asymptote is vertical line near which the function grows without bound.
The function f(x)=5x-15/x-3 is not asymptotic to the line x=3, because for x=3 f(x)=5*3-15/3-3=0/0=0 . So, there is a value for x=3 and the function f(x) does not grow near x=3 without bound.