Answer:
Explanation:
Comment
The question means that you are to break both numbers down in to prime factors. When you do, what do the numbers have in common
90: 2 * 3 * 3 * 5
126: 2 * 3 * 3 * 7
The bolded numbers are the primes in common
Primes in common (answer): 2 * 3 * 3 = 18