Answer:
Oblique asymptote is y= x- 6
Explanation:
f(x)=

To find out ablique asymptote we use long division
x - 6
------------------------------
x+2 x^2- 4x+ 8
x^2+ 2x
------------------------------ (Subtract it )
- 6x + 8
- 6x - 12
------------------------------(Subtract it)
-20
Quotient is the oblique asymptote
Oblique asymptote is y= x- 6