Answer:
72
Step-by-step explanation:
9 = 3^2
18 = 2 * 3^2
72 = 2^3 * 3^2
For LCM use common and not common factors with greater exponent.
Use 2^3 and 3^2.
LCM = 2^3 * 3^2 = 8 * 9 = 72
Answer: 72
