/in/foo.c: In function 'main':
/in/foo.c:9:5: error: invalid suffix "x" on integer constant
   y=3x-1;
     ^~
/in/foo.c:11:5: error: invalid suffix "x" on integer constant
   y=2x*x+4-5;
     ^~
/in/foo.c:13:10: error: invalid suffix "x" on integer constant
   y=sqrt(5x+10);
          ^~