10x
step-by-step explanation:
the greatest common factor 30 and 20 is 10
5 is a common factor of 30 and 20 but 10 is also a factor and 10 is greater than 5 so 5 will definitely not be apart of our answer
now the most amount of x's you factor our is just 1 factor of 1
so 10x the gcf of the terms in the polynomial