In this program, you’ll learn how to computes the roots of a quadratic equation when coefficients a, b and c are known.

To properly understand this example of a quadratic equation, you should have the knowledge of following Python programming topics:

- Python Input, Output and Import
- Python Variables and Data Types
- Python Operators

The Quadratic Formula uses the “** a**“, “

**“, and “**

*b***” from “**

*c*

*ax*^{2}**+**“, where “

*bx*+*c***“, “**

*a***“, and “**

*b***” are just numbers; they are the “numerical coefficients” of the quadratic equation they’ve given you to solve.**

*c*The Quadratic Formula: For ** ax^{2} + bx + c = 0**, the values of

*x*which are the solutions of the equation are given by:

**For Example: Solve x^{2} + 3x – 4 = 0**

This quadratic happens to factor:

*x*^{2} + 3*x* – 4 = (*x* + 4)(*x* – 1) = 0

we already know that the solutions are ** x = –4** and

**.**

*x*= 1How would my solution look in the Quadratic Formula?

Using *a* = 1, *b* = 3, and *c* = –4, my solution looks like this:

Then, as expected, the solution is ** x = –4**,

**.**

*x*= 1#### The standard form of quadratic equations:

ax2 + bx + c = 0, where a, b and c are real numbers and a ≠ 0

#### Program to Solve Quadratic Equation

```
# import complex math module
import cmath
a = 1
b = 5
c = 6
# To take coefficient input from the users
# a = float(input('Enter a: '))
# b = float(input('Enter b: '))
# c = float(input('Enter c: '))
# calculate the discriminant
d = (b**2) - (4*a*c)
# find two solutions
sol1 = (-b-cmath.sqrt(d))/(2*a)
sol2 = (-b+cmath.sqrt(d))/(2*a)
print('The solution are {0} and {1}'.format(sol1,sol2))
```

**Output**

```
Enter a: 1
Enter b: 5
Enter c: 6
The solutions are (-3+0j) and (-2+0j)
```

Here we have imported the `cmath`

module to perform complex square root. First, we calculate the discriminant and then find the two solutions of the quadratic equation.

You can change the value of a, b and c in the above program and test this program.

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Ask your questions and clarify your doubts on Python quadratic equations by commenting.** Python Documentation**