public class Convert {

	public static void main(String[] p) throws IOException{
		BufferedReader reader=new BufferedReader(
				new InputStreamReader(System.in));
		
		
		System.out.println("題目：aX2+bx+c=0,試求X=?");
		
		double DblA,DblB,DblC;
		System.out.println("請輸入a=?");
		String StrUserInput = reader.readLine();
		DblA=Double.parseDouble(StrUserInput);
		
		System.out.println("請輸入b=?");
		StrUserInput = reader.readLine();
		DblB=Double.parseDouble(StrUserInput);
		
		System.out.println("請輸入c=?");
		StrUserInput = reader.readLine();
		DblC=Double.parseDouble(StrUserInput);
		
		double DblResult=DblB*DblB-4*DblA*DblC;
		DblResult=java.lang.Math.sqrt(DblResult);
		
		//DecimalFormat Formater=new DecimalFormat("0.00"); 
		
		System.out.println("X = "+ (-DblB+DblResult) / (2*DblA)      );
		
		System.out.println(" 或 X = "+ String.valueOf((-DblB-DblResult)/(2*DblA)));
		
	}