Solve [tex][tex]$x^2 + 14x = -24$[/tex][/tex] by completing the square.

What is the solution set of the equation?

A. [tex][tex]$\{-12,-2\}$[/tex][/tex]

B. [tex][tex]$\{-7,7\}$[/tex][/tex]

C. [tex][tex]$\{-6,-4\}$[/tex][/tex]

D. [tex][tex]$\{-5,5\}$[/tex][/tex]



Answer :

To solve the equation [tex]\( x^2 + 14x = -24 \)[/tex] by completing the square, follow these steps:

1. Rewrite the Equation:
Start with the equation given:
[tex]\[ x^2 + 14x = -24 \][/tex]

2. Move the Constant to the Right Side:
The constant term [tex]\(-24\)[/tex] is already on the right side, so this step is already done.

3. Complete the Square:
To complete the square, find the term that needs to be added to both sides of the equation to form a perfect square trinomial on the left side.
- Take half of the coefficient of [tex]\(x\)[/tex], which is 14, divide it by 2 to get 7, and then square it:
[tex]\[ \left(\frac{14}{2}\right)^2 = 7^2 = 49 \][/tex]
- Add 49 to both sides of the equation:
[tex]\[ x^2 + 14x + 49 = -24 + 49 \][/tex]
- Simplify the right side:
[tex]\[ x^2 + 14x + 49 = 25 \][/tex]

4. Write the Left Side as a Perfect Square:
Now the left side can be written as a binomial squared:
[tex]\[ (x + 7)^2 = 25 \][/tex]

5. Solve for [tex]\(x\)[/tex]:
To find [tex]\(x\)[/tex], take the square root of both sides of the equation:
[tex]\[ x + 7 = \pm 5 \][/tex]
This gives us two equations to solve:
[tex]\[ x + 7 = 5 \quad \text{or} \quad x + 7 = -5 \][/tex]

6. Solve Each Equation:
- For [tex]\( x + 7 = 5 \)[/tex]:
[tex]\[ x = 5 - 7 = -2 \][/tex]
- For [tex]\( x + 7 = -5 \)[/tex]:
[tex]\[ x = -5 - 7 = -12 \][/tex]

So the solutions are [tex]\( -2 \)[/tex] and [tex]\( -12 \)[/tex]. Therefore, the solution set of the equation [tex]\( x^2 + 14x = -24 \)[/tex] is:
[tex]\[ \{-2, -12\} \][/tex]

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