Quadratic Equations

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

int main()
{
    printf("Calculator for Quadratic Equations.Please enter values for a, b and c. \n");

    float a, b, c;
    float x1, x2, d;

    printf("Enter a = ");
    scanf("%g", &a);

    printf("Enter b = ");
    scanf("%g", &b);

    printf("Enter c = ");
    scanf("%g", &c);

    if (a == 0)
    {
        x1 = - c / b;
        printf("x1 = %g\n", x1);
    }
    else if (b == 0)
    {
        if (-c / a < 0)
        {
            printf("Nqma reshenie\n");
        }
        else
        {
            x1 = sqrt(-c / a);
            x2 = -1 * sqrt(-c / a);

            printf("x1 = %g\n", x1);
            printf("x2 = %g\n", x2);
        }

    }
    else if (c == 0)
    {
        x1 = 0;
        x2 = -b / a;

        printf("x1 = %g\n", x1);
        printf("x2 = %g\n", x2);

    }
    else
    {
        d = b*b - 4 * a*c;
        if (d < 0)
        {
            printf("Nqma realni koreni\n");
        }
        else if (d == 0)
        {
            x1 = (-b) / (2 * a);
            printf("x1 = x2 = %g\n", x1);
        }
        else
        {
            x1 = (-b + sqrt(d)) / (2 * a);
            x2 = (-b - sqrt(d)) / (2 * a);

            printf("x1 = %g\n", x1);
            printf("x2 = %g\n", x2);
        }
    }

    system("PAUSE");
    return 0;
}