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# Python Program to Solve Quadratic Equation 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:

1. Python Input, Output and Import
2. Python Variables and Data Types
3. Python Operators

The Quadratic Formula uses the “a“, “b“, and “c” from “ax2 bx + c“, where “a“, “b“, and “c” are just numbers; they are the “numerical coefficients” of the quadratic equation they’ve given you to solve.

The Quadratic Formula: For ax2 + bx + c = 0, the values of x which are the solutions of the equation are given by:

For Example: Solve x2 + 3x – 4 = 0

x2 + 3x – 4 = (x + 4)(x – 1) = 0

we already know that the solutions are x = –4 and x = 1.

How 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 = –4x = 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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