How to Complete the Square in Quadratic Equations
How to Complete the Square in Quadratic Equations

How to Complete the Square in Quadratic Equations

Math High School 45 views

Quick Answer

To complete the square for the equation x² + 6x = 2, take half of the coefficient of x, square it, and add to both sides. This transforms the equation into a perfect square trinomial, simplifying the solution process.

Completing the square is a powerful technique used to solve quadratic equations. It allows us to rewrite the equation in a way that makes it easier to find the values of x. Let's break down the process step by step using the equation $$x^2 + 6x = 2$$ as our example.

### Step 1: Rearranging the Equation
First, we want to get the constant term on the right side of the equation. In our case, we already have:
$$x^2 + 6x = 2$$

### Step 2: Identifying the Coefficient of x
Next, take the coefficient of x, which is 6 in this case. The goal is to form a perfect square trinomial on the left side. To do this, we will divide the coefficient by 2:
$$6 \\ 2 = 3$$

### Step 3: Squaring the Result
Now, we square the result from the previous step:
$$3^2 = 9$$

### Step 4: Adding to Both Sides
We add this squared number (9) to both sides of the equation:
$$x^2 + 6x + 9 = 2 + 9$$
This simplifies to:
$$x^2 + 6x + 9 = 11$$

### Step 5: Writing as a Perfect Square
The left side of the equation can now be factored into a perfect square:
$$(x + 3)^2 = 11$$

### Step 6: Solving for x
Now we can solve for x by taking the square root of both sides:
$$x + 3 = \\pm \\sqrt{11}$$
This gives us:
$$x = -3 \\pm \\sqrt{11}$$

### Real-World Applications
Completing the square is not just a theoretical exercise; it has practical applications in various fields. For example, in physics, it can be used to derive the vertex form of a projectile’s motion equation, allowing one to determine the maximum height reached. In engineering, it can aid in optimizing design parameters.

### Conclusion
Completing the square is a valuable algebraic skill that helps in solving quadratic equations and understanding their properties. If you encounter quadratic equations in your studies, remember this method as it will make your problem-solving process much smoother. For more resources and practice problems, check out the 'equations' section on our site.

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