Spilled coefficients from quadratic equation into JAVA bugs

I am trying to spill coefficients from a quadratic equation and I got the function, but there is no output when I run this program. if the input string

  String eqn = "4x2-3x+45=0";
  equatin = quad(eqn);
  equatin="Answer = "+equatin;

      

        
        
        
      

    

the quad function above is called. A square function will split the coefficients into a quadratic equation. eg data input "4x2-3x + 45 = 0" AND the required output is 4 -3 45

public static String quad (final String equation)
{
  int a1 ;
  int b1 ;
  int c1 ;
  final String regex = "([+-]?\\d+)[xX]2([+-]\\d+)[xX]([+-]\\d+)=0";
  Pattern pattern = Pattern.compile(regex);

  Matcher matcher = pattern.matcher(equation);

  if (matcher.matches()) {
      a1= Integer.parseInt(matcher.group(1));
      b1 = Integer.parseInt(matcher.group(2));
      c1 = Integer.parseInt(matcher.group(3));
      String st6 ,st7,st8,st9;
      st7 = String.valueOf(a1);
      st8 = String.valueOf(b1);
      st9 = String.valueOf(c1);
      st6=st7+""+st8+""+st9;
      return st6;

  } else { /* throw exception or return null */
      String st5 = "wrong";
      return st5;
  }
}