1) 3(4 x 6) = (3x 4)6 is an example of the Associative Property of multiplication that states that we can associate the factors of multiplication, in a different order without altering the product.
3(4 x 6) = (3x 4)6
3(24) = (12)6
72 = 72
In addition to this, this property is very useful to avoid ambiguities and has an equivalent for the Addition operation.