The standard equation of circle when center is (h,k) and radius is 'r'

h = 2 and k = - 5, radius = 16
So equation of the circle is given by


Answer:f(x)=x2−6x−9 f ( x ) = x 2 - 6 x - 9. Replace f(x) f ( x ) with y y . y=x2−6x−9 y = x 2 - 6 x - 9. Interchange the variables. x=y2−6y−9 x = y 2 - 6 y - 9.
Step-by-step explanation:
If f(x) = 3x - 12 and x = 9
then substitute 9 in place of x
f(9) = 3(9) - 12
f(9) = 27 - 12
f(9) = 15