A slant asymptote occurs when the degree of the numerator is exactly one more than the degree of the denominator
Divide the numerator by the denominator using polynomial long division
Write the rational function as quotient plus remainder over denominator
The quotient is the slant asymptote if the remainder term goes to 0 as x approaches infinity or negative infinity
Express the asymptote as y = mx + b
Verify by checking that the difference between the function and the line approaches 0 as x approaches infinity or negative infinity