Answer:
9x^2 +6x -5
Explanation:
The x^2 terms are like terms and can be combined.
16x^2 -5 +6x -7x^2
= (16 -7)x^2 +6x -5
= 9x^2 +6x -5
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Additional comment
The expression is in standard form when the terms are in decreasing order by their degree.