Why does 2(5x*3y) have different answers when solved differently?

Question

If you multiply the inside first, you get the following:

2(5x*3y)

2(15xy)

30xy

On the other hand, if you multiply each by 2 first, you get this:

2(5x*3y)

10x*6y

60xy

Why does this happen if everything is multiplication and the commutative property should work?

Answer 1

you only multiply the 2 by one of the factors, not both

2(5x)(3y) = 2(15xy) = 30xy

or

2(5x)(3y) = 10x(3y) = 30y

or

2(5x)(3y) = 5x(6y) = 30y

but NOT 2(5x)(3y) = 10x(6y)

It's similar to

2(3)4) = 2(12)=24

or

2(3)4) = 6(4) = 24

or 2(3)(4) = 3(8) =24

but NOT

2(3)(4) = 6(8)