Given the equation:
\[
-20 = -4x - 6x
\]
Combine the like terms on the right-hand side:
\[
-4x - 6x = -10x
\]
So the equation simplifies to:
\[
-20 = -10x
\]
Step 2: Isolate the Variable
To isolate \( x \), divide both sides of the equation by \(-10\):
\[
x = \frac{-20}{-10}
\]
Simplifying the right-hand side:
\[
x = 2.0
\]
Step 3: Verify the Solution
Substitute \( x = 2.0 \) back into the original equation to verify:
\[
-4(2.0) - 6(2.0) = -8.0 - 12.0 = -20.0
\]
The left-hand side equals the right-hand side, confirming the solution is correct.