Answer:
15x^3
Explanation:
45x^5 = 3 * 3 * 5 * x * x * x * x * x
60x^3 = 2 * 2 * 3 * 5 * x * x * x
Now we see which factors are in common (shown in bold face).
45x^5 = 3 * 3 * 5 * x * x * x * x * x
60x^3 = 2 * 2 * 3 * 5 * x * x * x
GCF = 3 * 5 * x * x * x
GCF = 15x^3
Answer: 15x^3