Why the number of x is’s different in the printf statements in the functions?

#include <stdio.h>

void printHelp () {

printf (“\n”);

printf (“a: a(x) = x*x\n”);

printf (“b: b(x) = x*x*x\n”);

printf (“c: c(x) = x^2 + 2*x + 7\n”);

printf (“d: d(x) = x/2\n”);

printf (“q: quit\n”);

}

void a(float x) {

float v = x*x;

printf (” a(%.2f) = %.2f^2 = %.2f\n”, x, x, v);

} // end function a

void b(float x) {

float v = x*x*x;

printf (” a(%.2f) = %.2f^3 = %.2f\n”, x, x, v);

} // end function b

void c(float x) {

float v = x*x + 2*x + 7;

printf (” c(%.2f) = %.2f^2 + 2*%.2f + 7 = %.2f\n”, x, x, x, v);

} // end function c

void d(float x) {

float v = x/2;

printf (” d(%.2f) = %.2f/2 = %.2f\n “, x, v);

} // end function d

int menu () {

char selection;  float x;  printHelp ();

scanf (“%s”, &selection);

if (selection == ‘q’) return 1;

scanf (“%f”, &x);

if (selection == ‘a’) a(x);

if (selection == ‘b’) b(x);

if (selection == ‘c’) c(x);

if (selection == ‘d’) d(x);

return 0;

} // end function menu

int main() {

while (menu() == 0);

printf (“… bye …\n”);

return 0;

} // end main