用Java代码实现解一元二次方程

public class Equation {
private double a, b, c;

public Equation(double a, double b, double c) {
this.a = a;
this.b = b;
this.c = c;
}

public static void main(String[] args) throws Exception {
//j*(j-1) = 40;
//j*j - j - 40 =0
double[] results = new Equation(1, -1, -40).analyze();
for(int i = 0; i < results.length; i++){
System.out.println("j = " + results[i]);
}

}

public double[] analyze() throws Exception {
double delt = b * b - 4 * a * c;

if (delt < 0) {
throw new Exception("NO result");
} else if (delt == 0) {
double[] ary = { -b / (2 * a) };
return ary;
} else {
double[] ary = new double[2];
ary[0] = (-b + Math.sqrt(delt)) / (2 * a);
ary[1] = (-b - Math.sqrt(delt)) / (2 * a);

return ary;
}

}

}
----------testing
j = 6.84428877022476
j = -5.84428877022476