How do you find the asymptote for #(-7x + 5) / (x^2 + 8x -20)#?
You look for values of x for which there are no solutions possible, for example when the denominator is 0 that is a non-existent value. So -10 and 2 become asymptotes.
you will find all the values for which this function will yield a non-existent value. You can use the quadratic formula to solve for x or you can factorise.
Hence your solutions are -10 and 2 being your asymptotes.