To factor the expression \( 10x - 5 \) completely, we can look for the greatest common factor (GCF) of the terms.
The GCF of \( 10x \) and \( -5 \) is \( 5 \).
Now, we can factor out \( 5 \) from the expression:
\[ 10x - 5 = 5(2x - 1) \]
Thus, the completely factored form of the expression \( 10x - 5 \) is:
\[ 5(2x - 1) \]