We start with the equation:
\[
3 \sqrt{x + 2} = \sqrt{x + 4}
\]
Step 2: Square Both Sides
To eliminate the square roots, we square both sides of the equation:
\[
(3 \sqrt{x + 2})^2 = (\sqrt{x + 4})^2
\]
This simplifies to:
\[
9(x + 2) = x + 4
\]
Step 3: Rearrange the Equation
Next, we rearrange the equation to isolate terms involving \(x\):
\[
9x + 18 = x + 4
\]
Subtract \(x\) from both sides:
\[
8x + 18 = 4
\]
Then, subtract 18 from both sides:
\[
8x = 4 - 18
\]
This simplifies to:
\[
8x = -14
\]
Step 4: Solve for \(x\)
Now, we divide both sides by 8 to solve for \(x\):
\[
x = -\frac{14}{8} = -\frac{7}{4}
\]
Step 5: Verify the Solution
Finally, we check if \(x = -\frac{7}{4}\) satisfies the original equation:
Substituting \(x = -\frac{7}{4}\) into the left side:
\[
3 \sqrt{-\frac{7}{4} + 2} = 3 \sqrt{-\frac{7}{4} + \frac{8}{4}} = 3 \sqrt{\frac{1}{4}} = 3 \cdot \frac{1}{2} = \frac{3}{2}
\]
Now for the right side:
\[
\sqrt{-\frac{7}{4} + 4} = \sqrt{-\frac{7}{4} + \frac{16}{4}} = \sqrt{\frac{9}{4}} = \frac{3}{2}
\]
Since both sides are equal, \(x = -\frac{7}{4}\) is indeed a valid solution.