How do you find vertical, horizontal and oblique asymptotes for f (x) = (5x-15) / (2x 14) ?

For vertical asymptotes, find the values which make the function indetermine in this case x=-7, so this is the only vertical asymptote.

For horizontal asymptotes, find the limit when x tends to infinity:

= (5x/x-15/x) / (2x/x+14/x) = 5/2, this is the horizontal asymptote y=5/2

For obliques, you have to meet the degree of the numerator is exactly a greater degree than the denominator, in this case they are the same degree so no oblique asymptote.