What is the solution of [tex]\( \sqrt{x^2 + 49} = x + 5 \)[/tex]?

A. [tex]\( x = \frac{12}{5} \)[/tex]
B. [tex]\( x = -\frac{12}{5} \)[/tex]
C. [tex]\( x = -6 \)[/tex] or [tex]\( x = -3 \)[/tex]
D. No solution



Answer :

Sure, let's solve the equation [tex]\(\sqrt{x^2 + 49} = x + 5\)[/tex] step by step.

1. Isolate the square root:
[tex]\[ \sqrt{x^2 + 49} = x + 5 \][/tex]

2. Square both sides to eliminate the square root:
[tex]\[ \left(\sqrt{x^2 + 49}\right)^2 = (x + 5)^2 \][/tex]
[tex]\[ x^2 + 49 = x^2 + 10x + 25 \][/tex]

3. Simplify the equation:
Subtract [tex]\(x^2\)[/tex] from both sides:
[tex]\[ x^2 + 49 - x^2 = x^2 + 10x + 25 - x^2 \][/tex]
[tex]\[ 49 = 10x + 25 \][/tex]

4. Solve for [tex]\(x\)[/tex]:
Subtract 25 from both sides:
[tex]\[ 49 - 25 = 10x \][/tex]
[tex]\[ 24 = 10x \][/tex]
Divide both sides by 10:
[tex]\[ x = \frac{24}{10} \][/tex]
Simplify the fraction:
[tex]\[ x = \frac{12}{5} \][/tex]

So, the solution to the equation [tex]\(\sqrt{x^2 + 49} = x + 5\)[/tex] is:
[tex]\[ x = \frac{12}{5} \][/tex]

Let's verify the solution to ensure it's correct.

Substitute [tex]\(x = \frac{12}{5}\)[/tex] back into the original equation:
[tex]\[ \sqrt{\left(\frac{12}{5}\right)^2 + 49} = \frac{12}{5} + 5 \][/tex]
[tex]\[ \sqrt{\frac{144}{25} + 49} = \frac{12}{5} + \frac{25}{5} \][/tex]
[tex]\[ \sqrt{\frac{144 + 1225}{25}} = \frac{37}{5} \][/tex]
[tex]\[ \sqrt{\frac{1369}{25}} = \frac{37}{5} \][/tex]
[tex]\[ \frac{37}{5} = \frac{37}{5} \][/tex]

This confirms that [tex]\(x = \frac{12}{5}\)[/tex] is indeed the correct solution. Thus, the answer is:
[tex]\[ x = \frac{12}{5} \][/tex]