exponentials and power, replicating in C

So i have this excel line function as such:

I want to know how to write this in the arduino IDE.

So far i have this but i don't think it makes sense,

long result = 3*exp(7)*pow(x,-1);


float y(float x) {
  float result = 3E7 / x;
  return result;

How 'bout:
float result = 3*exp(7)*pow(x,-1);

Thanks guys. Smarter every day!