To solve the equation \(-1.2x - 3 = 0.8x + 0.6\), we will first move all the terms involving \(x\) to one side and the constant terms to the other side.
Starting with the original equation:
\[ -1.2x - 3 = 0.8x + 0.6 \]
Add \(1.2x\) to both sides:
\[ -3 = 0.8x + 1.2x + 0.6 \]
This simplifies to:
\[ -3 = 2.0x + 0.6 \]
Next, subtract \(0.6\) from both sides:
\[ -3 - 0.6 = 2.0x \]
This gives:
\[ -3.6 = 2.0x \]
Now, divide both sides by \(2.0\):
\[ x = \frac{-3.6}{2.0} \]
Calculating this gives:
\[ x = -1.8 \]
Rounding to the nearest tenth, the final solution is:
\[ \boxed{-1.8} \]