1) Expression 1: 16x^3 y
2) Expression 2: 24 xy^5
Procedure:
1) find the greatest common factor of the coefficients, 16 and 24:
16 = 2^4
24 = (2^3)*3
=> greatest common factor = 2^3 = 8
2) find the greatest common factor of x^3 y and xy^5
That is the common letters each raised to the lowest power:
=> xy
3) Then, the result is 8xy