12 because the rest of the numbers are all similar except 12
The least common denominator of 5/12 and -9/16
The answer is 48.
Now, we have to change the numerators also to make this a equal fraction to the first ones we had.
5*4 = 20
12*4 = 48
20/48
-9*3 = -27
16*3 = 48
-27/48
The number 20 is not a prime number.
