Quadratic equation solving in C

The Quadratic Formula: 
For ax2 + bx + c = 0, the value of x is given by:

Program

#include<stdio.h>
#include<conio.h>
#include<math.h>
main()
{
 double a,b,c,d,x1,x2;
 printf("Enter the co-efficient value of a:");
 scanf("%lf",&a);
 printf("Enter the co-efficient value of b:");
 scanf("%lf",&b);
 printf("Enter the co-efficient value of c:");
 scanf("%lf",&c);
 d=(b*b-4*a*c);
 if(d>0)
 {
 printf("\nRoots are real");
 x1=(-b+sqrt(d))/(2*a);
 x2=(-b-sqrt(d))/(2*a);
 printf("\nx=%.3lf , %.3lf",x1,x2);
 }
 else if(d==0)
 {
 printf("\nRoots are equal");
 x1=(-b+sqrt(d))/(2*a);
 printf("\nx=%.3lf",x1);
 }
 else
 {
 printf("\nRoots are imaginary");
    }
 getch();
}

Output

screenshot of program for quadratic equation

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