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Solve: [tex]\((x-4)^2 + 4 = 49\)[/tex]

A. [tex]\(x = 4 \pm 3 \sqrt{5}\)[/tex]
B. [tex]\(x = -4 \pm 2 \sqrt{10}\)[/tex]
C. [tex]\(x = \pm 7\)[/tex]
D. [tex]\(x = -4 + \sqrt{45}\)[/tex]


Sagot :

To solve the equation [tex]\((x-4)^2 + 4 = 49\)[/tex], let's go through the solution step-by-step:

1. Simplify the equation:

Start by rewriting the given equation:
[tex]\[ (x-4)^2 + 4 = 49 \][/tex]

2. Isolate [tex]\((x-4)^2\)[/tex]:

Subtract 4 from both sides to isolate the squared term:
[tex]\[ (x-4)^2 + 4 - 4 = 49 - 4 \][/tex]
[tex]\[ (x-4)^2 = 45 \][/tex]

3. Solve for [tex]\(x-4\)[/tex]:

To solve for [tex]\(x-4\)[/tex], take the square root of both sides:
[tex]\[ \sqrt{(x-4)^2} = \sqrt{45} \][/tex]
Remember that taking the square root gives both positive and negative solutions:
[tex]\[ x-4 = \pm \sqrt{45} \][/tex]

4. Simplify [tex]\(\sqrt{45}\)[/tex]:

Note that [tex]\(\sqrt{45}\)[/tex] can be simplified:
[tex]\[ \sqrt{45} = \sqrt{9 \times 5} = \sqrt{9} \times \sqrt{5} = 3\sqrt{5} \][/tex]
Therefore, we have:
[tex]\[ x-4 = \pm 3\sqrt{5} \][/tex]

5. Solve for [tex]\(x\)[/tex]:

Isolate [tex]\(x\)[/tex] by adding 4 to both sides:
[tex]\[ x = 4 \pm 3\sqrt{5} \][/tex]

6. Conclude the solutions:

The solutions to the equation [tex]\((x-4)^2 + 4 = 49\)[/tex] are:
[tex]\[ x = 4 - 3\sqrt{5} \quad \text{and} \quad x = 4 + 3\sqrt{5} \][/tex]

Hence, the solutions are:
[tex]\[ x = 4 - 3\sqrt{5} \quad \text{and} \quad x = 4 + 3\sqrt{5} \][/tex]

None of the other options provided ([tex]\(x= -4 \pm 2 \sqrt{10}\)[/tex], [tex]\(x= \pm 7\)[/tex], [tex]\(x=-4 + \sqrt{45}\)[/tex]) match our found solutions. The correct solution is indeed:
[tex]\[ x = 4 - 3\sqrt{5} \quad \text{and} \quad x = 4 + 3\sqrt{5} \][/tex]