To solve the equation \( 43 - (24 - x) = 20 \), follow these steps:

1. Distribute the negative sign inside the parentheses:
\[
43 - 24 + x = 20
\]

2. Simplify the left side of the equation:
\[
19 + x = 20
\]

3. Subtract 19 from both sides to isolate \( x \):
\[
x = 20 - 19
\]

4. Simplify the right side:
\[
x = 1
\]

So, the solution to the equation is \( x = 1 \).