6. find any points of discontinuity for the rational function.

y = x-8/x^2 +6x-7

x = 1, x = 7
x = 8
x = 1, x = –7
x = –1, x = 7

7. describe the vertical asymptote(s) and hole(s) for the graph of y = x-5/x^2 +4x +3

asymptotes: x = –3, –1 and no holes.
asymptote: x = –3 and hole: x = –5
asymptotes: x = –3, –1 and hole: x = –5
asymptote: x = –5 and hole: x = –3

8. find the horizontal asymptote of the graph of y = -4x^6 +6x +3/8x^6 +9x+3

y = 1
y = –1/2
y = 0
there is no horizontal asymptote.