Let Find the values of k for which the equation x=k is a vertical asymptote of the graph of y=f(x). Enter all such values, separated by commas.
Factor both the numerator and the denominator:
f(x) = [ 2(x + 5)(x - 5) ] / [ (x + 5)(x - 3) ]
Since the factor (x + 5 ) is found in both the numerator and the denominator, it produces a hole in the function at x = -5.
Cancelling out that term, we have: f(x) = [ 2(x - 5) ] / [ (x - 3) ]
There will be a vertical asymptote at x = 3 (because it makes the denominator zero).