Since the only thing that changed was the grouping (the parentheses), but the 9, 5, and 2 are in the same order, this is the associative property of multiplication.
In the second line, you'd put 45 and then 90:
In the third line, you'd put 10 and then 90:
The idea here is that regrouping an expression where everything is multiplication will not change the final result. It changes the order of operations, since things in parentheses are done first, but not the final outcome.