Define variables and write each sentence in function notation.?

Question

1.) Auto registration costs 1% of the current value of the car. Auto registration cost is a function of the value of the car.
2.) The value of a sphere is a functions of a radius. Volume is 4/3pi times the cube of the radius.

Somebody help me this , i have my ans. but i want to compare .

Answer 1

#1: let x be the current value of the car, and f(x) be the price of auto registration. Then f(x)=x/100
#2: Let r be the radius of a sphere, and f(r) be the volume of that sphere. Then f(r)=4/3πr³

Answer 2

to be a function, each and every x cost has to have precisely one y cost. evaluate x = a million. Then 3x+2 = 3(a million)+2=5. Now, what number y values are more advantageous than or equivalent to this? Infinitely, as an party 6, 7, 8..... all are more advantageous than 5.