I don't know how to find the GCF if the variables are different. For example, 48a^3 and 16b^5.

To find the greatest common factor (GCF) of two terms with different variables, such as 48a^3 and 16b^5, follow these steps:

Step 1: Break down each term into its prime factors.

For 48a^3:
- 48 can be divided by 2, resulting in 2 * 24.
- 24 can be divided by 2, resulting in 2 * 2 * 12.
- 12 can be divided by 2, resulting in 2 * 2 * 2 * 3.
- Finally, we have 48 = 2 * 2 * 2 * 2 * 3 = 2^4 * 3.

For 16b^5:
- 16 can be divided by 2, resulting in 2 * 8.
- 8 can be divided by 2, resulting in 2 * 2 * 4.
- 4 can be divided by 2, resulting in 2 * 2 * 1.
- Finally, we have 16 = 2 * 2 * 2 * 2 = 2^4.

Step 2: Identify the common factors of both terms.

In this case, the only common factor is 2^4, as there are no common variables between 48a^3 and 16b^5.

Step 3: Combine the common factors.

Since the common factor is 2^4 (which is 16), the GCF of 48a^3 and 16b^5 is 16.

Therefore, the GCF of 48a^3 and 16b^5 is 16.