To solve for the measure of angle P-Q-S (which is \( x \) degrees) given that angle R-Q-S measures \( x - 60 \) degrees, we can set up the equation based on the fact that the sum of the angles in a straight angle (180 degrees) must equal the measure of angle P-Q-S plus the measure of angle R-Q-S.
The equation can be formulated as:
\[ x + (x - 60) = 180 \]
Simplifying this equation:
\[ 2x - 60 = 180 \]
Now we can see that this corresponds to option A:
A. \( 2x - 60 = 180 \)
Therefore, the correct answer is A.