To rewrite \( 25 + 75 \) using their greatest common factor (GCF) and multiplication, first find the GCF of 25 and 75.
The GCF of 25 and 75 is 25.
Now, we can factor out the GCF from the sum:
\[ 25 + 75 = 25(1 + 3) \]
So the expression can be rewritten as:
\[ 25(1 + 3) \]
Thus, the complete representation is \( 25(1 + 3) \).