What is the Big-O notation of the following?

What is the Big-O notation of the following?

1) 2n + 3n log n + 15n^1.1

2) 3n + 5n (log n)⁵⁵⁵ + n³

3) 2n (3 + log n + n² )

4) 2n⁵⁵ + 2ⁿ

5) 2n (log n)⁴ + n²

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Here is what I got for my answers (please confirm if I’m right):

1) O(n log n)

2) O(n log n⁵⁵⁵)

3) O(n³)

4) O(n⁵⁵)

5) O(n²)