30x^3 = 2 * 3 * 5 * x * x * x
110x^4 = 2 * 5 * 11 * x * x * x * x
60x^8 = 2 * 2 * 3 * 5 * x * x * x * x * x * x * x * x
The GCF is made of the factors that appear in both 30x^3, 100x^4, and 60x^8. In this case that's 2 * 5 * x * x * x * x = 10x^4.
Answer: The GCF of 30x^3, 100x^4, and 60x^8 is 10x^4.