What is the greatest common factor of 18a^4b^3 and 21a^8b^3?
The greatest common factor of two numbers is the largest number that can evenly divide both numbers.
To find the greatest common factor of 18a^4b^3 and 21a^8b^3, we need to look for the highest power of each variable that appears in both numbers.
18 = 2 * 3 * 3
21 = 3 * 7
The common factor with the highest power of 'a' is a^4 and the common factor with the highest power of 'b' is b^3.
Therefore, the greatest common factor of 18a^4b^3 and 21a^8b^3 is 3a^4b^3.