How to solve a quadratic equation by completing the square

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What is Completing the Square?
Completing the square is a process to convert a quadratic equation from
the general form y = ax2 + bx + c
to the vertex form y = a(x - h)2 + k
The vertex form can be used to find the vertex of a quadratic equation and to solve a quadratic equation.

The following diagram gives the vertex form of a quadratic equation. Scroll down the page for more examples and solutions.
Vertex Form of a Quadratic Equation

Completing the Square (Tutorial 1)

Completing the Square (Tutorial 2)

Completing the Square (Tutorial 3)

How to Solve a Quadratic Equation by Completing the Square?

Try the free Mathway calculator and problem solver below to practice various math topics. Try the given examples, or type in your own problem and check your answer with the step-by-step explanations.
Mathway Calculator Widget

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