the numerator is a degree of 2, higher than the denominator's degree of 1, so there is a oblique (slant) asymptote, which is the quotient.
use long division to find the quotient:
x +8
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x-2 I x² +6x -9
x² -2x
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8x -9
you don't have to finish, because the remainder doesn't matter. the answer is y=x+8