/in/foo.c: In function 'main':
/in/foo.c:10:5: warning: implicit declaration of function 'pow' [-Wimplicit-function-declaration]
   y=pow(x,2)*2+4*x-5;
     ^~~
/in/foo.c:10:5: warning: incompatible implicit declaration of built-in function 'pow'
/in/foo.c:10:5: note: include '<math.h>' or provide a declaration of 'pow'
/in/foo.c:12:8: warning: incompatible implicit declaration of built-in function 'pow'
      y=pow(5*x+10,0.5);
        ^~~
/in/foo.c:12:8: note: include '<math.h>' or provide a declaration of 'pow'
/in/foo.c:14:5: warning: incompatible implicit declaration of built-in function 'pow'
   y=pow(x,3);
     ^~~
/in/foo.c:14:5: note: include '<math.h>' or provide a declaration of 'pow'
/in/foo.c:15:2: warning: 'y' may be used uninitialized in this function [-Wmaybe-uninitialized]
  printf("%.3f",y);
  ^~~~~~~~~~~~~~~~