Solve for [tex]$x$[/tex], given the equation [tex]\sqrt{x-5}+7=11[/tex].

A. [tex]x=21[/tex], solution is extraneous
B. [tex]x=21[/tex], solution is not extraneous
C. [tex]x=81[/tex], solution is extraneous
D. [tex]x=81[/tex], solution is not extraneous



Answer :

Let's solve the given equation step-by-step to find the value of [tex]\( x \)[/tex] and determine if the solution is extraneous or not.

The equation is:
[tex]\[ \sqrt{x - 5} + 7 = 11 \][/tex]

Step 1: Isolate the square root term.

Subtract 7 from both sides of the equation:
[tex]\[ \sqrt{x - 5} = 11 - 7 \][/tex]
[tex]\[ \sqrt{x - 5} = 4 \][/tex]

Step 2: Square both sides to eliminate the square root.

By squaring both sides, we get:
[tex]\[ (\sqrt{x - 5})^2 = 4^2 \][/tex]
[tex]\[ x - 5 = 16 \][/tex]

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

Add 5 to both sides to solve for [tex]\( x \)[/tex]:
[tex]\[ x = 16 + 5 \][/tex]
[tex]\[ x = 21 \][/tex]

Step 4: Verify the solution to check if it is extraneous.

Substitute [tex]\( x = 21 \)[/tex] back into the original equation to see if it holds true:
[tex]\[ \sqrt{21 - 5} + 7 = 11 \][/tex]
[tex]\[ \sqrt{16} + 7 = 11 \][/tex]
[tex]\[ 4 + 7 = 11 \][/tex]
[tex]\[ 11 = 11 \][/tex]

Since the left-hand side equals the right-hand side, the solution is correct and not extraneous.

Thus, the solution is [tex]\( x = 21 \)[/tex], and it is not extraneous.

So, the correct answer is:

[tex]\[ x = 21, \text{ solution is not extraneous} \][/tex]