To solve for \( x \) in the equation \(-20 = -5 + 3x\), follow these steps:
- Add 5 to both sides of the equation to isolate the term with \( x \):
\[ -20 + 5 = 3x \]
- This simplifies to:
\[ -15 = 3x \]
- Now, divide both sides by 3 to solve for \( x \):
\[ x = \frac{-15}{3} \]
- Simplifying the right side gives:
\[ x = -5 \]
So the solution is:
\[ \boxed{-5} \]