Answer:
12900
Step-by-step explanation:
umm first you write down the number of zeros (but only the zeros at last if a zero comes in middle or between other numbers, then you must have to multiply it) and then multiply the remaining numbers. I am not good at explaining. ;)
21= 1,3,7,21
30= 1,2,3,5,6,10,15,30
common factors= 1,3
B) x = y^2 because it fails the vertical line test making it not a function