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Select the correct answer.

Determine the solutions to the following equation:
[tex]\[ (x-4)^2 = 81 \][/tex]

A. [tex]\( x = -13 \)[/tex] and [tex]\( x = 5 \)[/tex]
B. [tex]\( x = -5 \)[/tex] and [tex]\( x = 13 \)[/tex]
C. [tex]\( x = -4 \)[/tex] and [tex]\( x = 9 \)[/tex]
D. [tex]\( x = -9 \)[/tex] and [tex]\( x = 4 \)[/tex]


Sagot :

To determine the solutions to the equation [tex]\((x-4)^2 = 81\)[/tex], follow these steps:

1. Rewrite the equation in standard form:
[tex]\[ (x - 4)^2 = 81 \][/tex]

2. Take the square root of both sides:
When we take the square root of both sides of the equation, we must remember that the square root of a number can be both positive and negative. Therefore:
[tex]\[ \sqrt{(x-4)^2} = \pm \sqrt{81} \][/tex]
Simplifying, we have:
[tex]\[ x - 4 = \pm 9 \][/tex]

3. Solve the equation for [tex]\(x\)[/tex] by considering both the positive and negative cases:

- For the positive case:
[tex]\[ x - 4 = 9 \][/tex]
Add 4 to both sides:
[tex]\[ x = 9 + 4 \][/tex]
[tex]\[ x = 13 \][/tex]

- For the negative case:
[tex]\[ x - 4 = -9 \][/tex]
Add 4 to both sides:
[tex]\[ x = -9 + 4 \][/tex]
[tex]\[ x = -5 \][/tex]

4. List the solutions:
The solutions to the equation [tex]\((x-4)^2 = 81\)[/tex] are:
[tex]\[ x = -5 \quad \text{and} \quad x = 13 \][/tex]

Therefore, the correct answer is [tex]\(x = -5\)[/tex] and [tex]\(x = 13\)[/tex]. Thus, the correct choice from the provided options is:
[tex]\[ x = -5 \text{ and } 13 \][/tex]