To find the value of \( x \) given the mean of the numbers \( 104, 137, 154, 131, x \) is 130, we can set up the equation based on the definition of the mean.
The mean is calculated as the sum of all values divided by the number of values:
\[ \text{Mean} = \frac{\text{Sum of values}}{\text{Number of values}} \]
In this case, the number of values is 5 (the four given numbers plus \( x \)). Therefore, the equation for the mean is:
\[ 130 = \frac{104 + 137 + 154 + 131 + x}{5} \]
Now, let's calculate the sum of the known values:
\[ 104 + 137 + 154 + 131 = 526 \]
Now substituting that back into the equation:
\[ 130 = \frac{526 + x}{5} \]
Next, we multiply both sides of the equation by 5 to eliminate the fraction:
\[ 130 \cdot 5 = 526 + x \]
\[ 650 = 526 + x \]
Now, we isolate \( x \):
\[ x = 650 - 526 \]
\[ x = 124 \]
Thus, the value of \( x \) is \( \boxed{124} \).