public class Equation {

    public static double a;
    public static double b;
    public static double c;

    public int kol;

    public int kolkorni() {
        if (a != 0) {
            if (b * b - 4 * a * c > 0) {
                kol = 2;
            }
        }
        if ((a == 0) && (b != 0) && (c != 0)) {
            kol = 1;
        }
    }
}

void printA(){
  System.out.println(a);
}

public static double a;
public static double b;
public static double c;

public class Equation {

    private double a;
    private double b;
    private double c;

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

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

    public double getA() {
        return a;
    }

    public double getB() {
        return b;
    }

    public double getC() {
        return c;
    }

    public int resultsNuber() {
        if (isQuadratic()) {
            double discriminant = this.getDiscriminant();
            if (discriminant > 0) {
                return 2;
            } else if (discriminant == 0.0) {
                return 1;
            } else {
                return 0;
            }
        }

        if (isLinear()) {
            return 1;
        }

        return Integer.MAX_VALUE;
    }

    private boolean isQuadratic() {
        return a != 0;
    }

    private boolean isLinear() {
        return (a == 0) && (b != 0) && (c != 0);
    }

    private double getDiscriminant() {
        return b*b - 4*a*c;
    }

    public void toString() {
        return "" + a + "*x^2 + " + b +"*x + " + c + " = 0";

    }
}

public abstract class Equation {
    protected double static epsilon=0.0000001; //значение зависит от задачи
    protected double a;
    protected Equation(double a) {this.a=a;}
    protected boolean isZero(double x) {
        if(Math.abs(x) <= epsilon)
           return true;
        return false;
    }
    public abstract int getNumberOfRoots();
}

public class LinearEquation extends Equation {
    protected double b;
    public LinearEquation(double a, double b) {super(a); this.b=b;}
    public int getNumberOfRoots() {
       if(this.isZero(b)
          return 0;
       return 1;
    }

public class QuadraticEquation extends LinearEquation {
    protected double c;
    public LinearEquation(double a, double b, double c) {super(a, b); this.c=c;}
    public int getNumberOfRoots() {
       //blah-blah
    }
}