2-4

#include<stdio.h>
int main(void)
{
   double x,y;
   printf("Enter x(x>=0):\n");
   scanf("%lf",&x);
   if(x<=15){
    y=4*x/3;
   }
   else{
   y=2.5*x-10.5;
   }
   printf("y=f(%f)=%.2f\n",x,y);
    return 0;
}