# Write Quadratic Equation

**English**UK

Quadratic Equation
may be expressed as a product

a(x-x1)(x-x2) = 0,where

**x1**and

**x2**are the solutions of equation, so called roots. After opening the brackets you receive well known form

a*x**2 + b*x + c = 0.This is what you should do in this mission. You have input list with integers -

**a, x1 [, x2]**. If it has length 2, it means,

**x1 == x2**: equation has two equal roots (one distinct root). Your function should return quadratic equation as a string. Pay attention to specific cases. Use Quadratic Formula Calculator for recheck. Good luck!

**Input:** List with 2-3 integers.

**Output:** String.

**Examples:**

assert quadr_equation([2, 4, 6]) == "2*x**2 - 20*x + 48 = 0" assert quadr_equation([-2, 4, 6]) == "-2*x**2 + 20*x - 48 = 0" assert quadr_equation([2, 4, -4]) == "2*x**2 - 32 = 0" assert quadr_equation([2, 4, 0]) == "2*x**2 - 8*x = 0"

**How it’s used:**
*Practice of automatic representing human-friendly view of equations.*

**Preconditions:**

*a != 0; abs(a) == 1 -> '[-]x**2'; a != abs(1) - > '[-]a*x**2'**exactly one whitespace around signs: [-]a*x**2 sign b*x sign c = 0**abs(b) == 1 -> [-]a*x**2 sign x sign c = 0**keep correct view and spacing when x1=x2=0, x1 or x2 = 0, x1=-x2*

CheckiO Extensions allow you to use local files to solve missions. More info in a blog post.

In order to install CheckiO client you'll need installed Python (version at least 3.8)

Install CheckiO Client first:

pip3 install checkio_client

Configure your tool

checkio --domain=py config --key=

Sync solutions into your local folder

checkio sync

(in beta testing) Launch local server so your browser can use it and sync solution between local file end extension on the fly. (doesn't work for safari)

checkio serv -d

Alternatevly, you can install Chrome extension or FF addon

checkio install-plugin

checkio install-plugin --ff

checkio install-plugin --chromium

Read more here about other functionality that the checkio client provides. Feel free to submit an issue in case of any difficulties.