# New Program to Solve Quadratic equation in C++

Here we will a write a program to solve quadratic equation in C++ programming language. Let’s first understand how to solve a quadratic equation:

Let’s take the quadratic equation as: ax²+bx+c=0

### How program works:

• Take the values for a, b and c (double type).
• if, a = b = 0 then invalid equation
• if b² -4ac < 0 then the real roots
• if b² -4ac > 0 , x1= (-b+√(b² -4ac))/2a , x1= (-b -√(b² -4ac))/2a
• The C++ function for √x is sqrt(x).
• Include math.h for using the sqrt() function.

Now let’s write the program for the same.

Here is a program to solve Quadratic equation in Python

### Program to solve Quadratic equation in C++

```#include<iostream>
#include<cmath>
#include<cstdlib>
#include<cstring>
using namespace std;
int main()
{
double a,b,c,x1,x2;
char x;
cout<<"enter the value of a=";
cin>>a;
cout<<"enter the value of b=";
cin>>b;
cout<<"enter the value of c=";
cin>>c;
cout<<"*x*x+"<<b;
cout<<"*x+"<<c<<endl;
if

(a==0 && b==0)
cout<<"not a valid equation";
if

(a==0 && b!=0)
{
x1=-(c/b);

cout<<endl;
cout<<"root="<<x1;
cout<<endl;
}
if ((b*b-4*a*c)>0)
{
x2=(b*b)-(4*a*c);
x1=-b+sqrt(x2);
cout<<"root="<<x1<<endl;
}
if ((b*b-4*a*c)<0)
{
cout<<"not a real root"<<endl;
}
system("pause");
return 0;
}```

### OUTPUT:

```enter the value of a=15
enter the value of b=16
enter the value of c=21