The greatest common factor (GCF) of 28 and 16 can be determined by finding the factors of each number.
The factors of 28 are: 1, 2, 4, 7, 14, and 28.
The factors of 16 are: 1, 2, 4, 8, and 16.
The greatest common factor (the largest number that appears in both lists) is 4.
So, the GCF of 28 and 16 is 4.
Next, to express \( 28 + 16 \) using the GCF, we can factor both numbers with the GCF. We can write:
\[ 28 + 16 = 4(7) + 4(4) = 4(7 + 4) \]
Therefore, the expression that uses the GCF and is equivalent to \( 28 + 16 \) is 4(7 + 4).