To solve for \( x \) in the equation:
\[ -20 = -8 + 3x \]
First, add 8 to both sides:
\[ -20 + 8 = 3x \]
This simplifies to:
\[ -12 = 3x \]
Next, divide both sides by 3:
\[ x = \frac{-12}{3} \]
This simplifies to:
\[ x = -4 \]
So, the solution is:
\[ x = -4 \]