To solve the equation \(-5x - 12x = -85\), we first combine the terms on the left side:
\[ -5x - 12x = -17x \]
So the equation becomes:
\[ -17x = -85 \]
Next, to solve for \(x\), we divide both sides by \(-17\):
\[ x = \frac{-85}{-17} \]
Since both the numerator and the denominator are negative, we can simplify this:
\[ x = \frac{85}{17} \]
Now, performing the division:
\[ x = 5 \]
Therefore, the solution is:
\[ \boxed{5} \]