Quadratic equation calculator

/*
    Discriminant calculator in C
    Author: Kyojin96
    Date: 9.11.2015
*/

#include <stdio.h>
#include <stdlib.h>
#include <math.h>

int main()
{
    /* Variables */
    int a, b, c;
    float x1, x2, D, re, im;


    /* We need input for a, b & c */
    printf("a = "); scanf("%d", &a);
    printf("b = "); scanf("%d", &b);
    printf("c = "); scanf("%d", &c);

    /* if both equal 0 then it's degenerated */
    if(a == 0 && b == 0)
    {
        printf("The equation is degenerated\n");
    }
    /* in this case x = -c/b */
    else if(a == 0 && b != 0)
    {
        x1 = -c/b;
        printf("The equation has only one root x1 = %f\n", x1);
    }
    /* Check c first for optimisation */
    else if(c == 0 && a != 0 && b != 0)
    {
        x1 = -b/a;
        x2 = 0;
        printf("The equation has two roots x1 = %f and x2 = %f\n", x1, x2);
    }
    /* if all are bigger than 0 then calculate discriminant */
    else if(a != 0 && b != 0 && c != 0)
    {
        /* Use math funcs to power b a.k.a b^2 */
        float bPowered = pow(b, 2);
        D = bPowered - 4 * a * c;

        /* If discriminant is more than 0, it has 2 roots */
        if(D > 0)
        {
            x1 = (-b + sqrt(D))/(2 * a);
            x2 = (-b - sqrt(D))/(2 * a);
            printf("The equation has 2 roots x1 = %f and x2 = %f\n", x1, x2);
        }
        /* If it's less than 0, it has real and imaginary numbers */
        else if(D < 0)
        {
            re = -b/2*a;
            im = sqrt(fabs(D))/2*a;
            printf("The equation has real part re = %f and imaginery im = %f\n", re, im);
        }
        /* Else if it's 0 then it has two equal roots */
        else
        {
            x1 = -b/2*a;
            printf("The equation has two equal roots x1 = x2 = %f\n", x1);
        }
    }

    /* Pause the console app */
    system("pause");

    return 0;
}