For the polynomial 6xy^2 - 5x^2y^?+9x^2 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?

For the polynomial 6xy2 5x2y9x2 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 class=