Find the greatest common factor of these three expressions.
\[
28 y^{2}, 42 y^{5}, \text { and } 70 y
\]
So, the final answer is \(\boxed{14y}\).
Step 1 :Find the GCF of the coefficients 28, 42, and 70. The greatest common factor of these three numbers is 14.
Step 2 :Find the lowest power of y in the three expressions 2, 5, and 1. The lowest of these is 1.
Step 3 :Therefore, the greatest common factor of the three expressions is \(14y\).
Step 4 :So, the final answer is \(\boxed{14y}\).