To find the greatest common factor (GCF) of 88s^2t and 40st^2, we first need to break down each term into its prime factors. 88 = 2^3 * 11, s^2 has no prime factors other than s itself, t has no prime factors other than t itself. 40 = 2^3 * 5, s has no prime factors other than s itself, t^2 = t * t. Comparing the prime factors between the two terms, the GCF is 8st.
The GCF is 8st.