Expressions 2) and 3) are equivalent to (5 ⋅ x) ⋅ 3.
The expression (5 ⋅ x) ⋅ 3 is equivalent to:
5 ⋅ (3 ⋅ x)
(3 ⋅ 5) ⋅ x = 15 ⋅ x
Therefore, expressions 2) and 3) are equivalent to (5 ⋅ x) ⋅ 3.
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