To solve for \( x \), we need more context regarding how the degrees relate to each other. Because you've given two angles, \( 51^\circ \) and \( 3x^\circ \), it seems you might be looking at whether these angles are related in a certain way (like forming a triangle, being supplementary, complementary, etc.).
Let's assume you're asking if these angles are supplementary, meaning their sum is \( 180^\circ \).
So, we set up the equation:
\[ 51 + 3x = 180 \]
Now, subtract \( 51 \) from both sides:
\[ 3x = 180 - 51 \] \[ 3x = 129 \]
Next, divide by \( 3 \):
\[ x = \frac{129}{3} \] \[ x = 43 \]
Thus, the value of \( x \) is \( 43 \) degrees.
If you meant a different relationship between the angles, please specify!