Answer:
C. 5x + 3y cannot be factored
Explanation:
We can factor A. 7y + 42 and get 7 (y + 6)
We can factor B. 9y + 6 and get 3 (3y + 2)
Lastly, we can factor D. 17a + 34 and get 17 ( a + 2)
Which leaves us with C which cannot be factored
Why cant it be factored?
It cannot be factored any further.
It cannot be factored with rational numbers.
A rational number is a number that can be expressed as the ratio of two integers.