For the polynomial 6 x y squared minus 5 x squared y to the ? th power plus 9 x squared to be a trinomial with a degree of 3 after it has been fully simplified, what is the missing exponent of the y in the second term?

The first term, 6xy², has degree 1 + 2 = 3, and the last term, 9x², has degree 2. If the missing exponent is 1, the middle term is −5x²y, which has degree 3, so the polynomial has degree 3 and remains a trinomial. An exponent of 0 would make the middle term −5x², which combines with 9x² and leaves only two terms.

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