/**

 * 求解 一元二次方程ax^2+bx+c=0

 */

public class Main {

public static void main(String[] args) {

// x*x + 3*x - 4 = 0

double a = 1.0;

double b = 3.0;

double c = -4.0;

double x1 = 0;

double x2 = 0;

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

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

System.out.println(x1+","+ x2);

System.out.println(x1 == 1 && x2 == -4 ? "测试通过":"测试失败");

}

}