部分借鉴，仅供参考

解题思路:

注意事项:

参考代码:

import java.util.Scanner;

public class Main {

public static void main(String[] args) {

Scanner reader = new Scanner (System.in);

double a = reader.nextDouble();

double b = reader.nextDouble();

double c = reader.nextDouble();

double x1;

double x2 ;

double s;

double x;

if(Math.pow(b, 2)-4*a*c>0) {

x1 = ((-b+Math.sqrt(Math.pow(b, 2)-4*a*c))/2*a);

x2 = ((-b-Math.sqrt(Math.pow(b, 2)-4*a*c))/2*a);

System.out.println("x1="+String.format("%.3f", x1)+" x2="+String.format("%.3f", x2));

}

else if (Math.pow(b, 2)-4*a*c==0){

x1 = (-b/2*a);

x2 = x1;

System.out.println("x1="+String.format("%.3f", x1)+" x2="+String.format("%.3f", x2));

}

else {

s = (-b/(2*a));

x = Math.sqrt((4*a*c-b*b))/(2*a);

System.out.println("x1="+String.format("%.3f", s)+"+"+String.format("%.3f", x)+"i"+" x2="+String.format("%.3f", s)+"-"+String.format("%.3f", x)+"i");

}

}

}