BT giải PT bậc 2

//Giai PT bac 2 //By CQH
//Trình Công Quang //MSSV: 12520344
# include <stdio.h>
# include <conio.h>
# include <math.h>

void main ()

{
    float a,b,c;
    float delta;
    printf("\nNhap cac he so cua PT:\n");
    printf("\na = ");
    scanf("%f",&a);
    printf("\nb = ");
    scanf("%f",&b);
    printf("\nc = ");
    scanf("%f",&c);

    if (a!=0)
        {
            delta=b*b-4*a*c;

        if (delta > 0)
            printf ("\nPT co 2 nghiem phan biet : x1 = %.2f va x2 = %.2f\n\n", (-b+sqrt(delta))/(2*a), (-b-sqrt(delta))/(2*a) );
        else if (delta == 0 )
            printf ("\nPT co nghiem kep : x1 = x2 = %.2f\n\n", (-b)/(2*a ));
        else
            printf ("\nPT vo nghiem!\n\n");
        }
    else
        {
            if (b==0)
                {
                    if (c==0)
                    printf("\nPT vo so nghiem\n\n");
                    else
                    printf("\nPT vo nghiem\n\n");
                }
            else
                printf("\nPT co 1 nghiem: x = %.2f\n\n", -c/a);
        }
        printf("\nBam phim bat ki de thoat........... ");
        getch();
}
int pressout(int argc, char *argv[])
{
    getchar();
    return 0;
}