a,\(4\notinƯC\left(12,18\right)\)
b,\(6\inƯC\left(12,18\right)\)
c, \(2\inƯC\left(4,6,8\right)\)
d, \(4\notinƯC\left(4,6,8\right)\)
e \(80\notin BC\left(20,30\right)\)
g, \(60\notin BC\left(4,6,8\right)\)
h, \(12\notin BC\left(4,6,8\right)\)
I, \(24\in BC\left(4,6,8\right)\)