Setting the denominator to zero can help find the points of discontinuity for the rational function.
The denominator is (x+9)(x+7). Equating each factor to zero, the results are:
x+9 = 0;
x=-9x+7 = 0;
x=-7Substituting each of the values of x to the equation makes y undefined.
Finding also the oblique asymptotes if needed, one uses the long division process:


The oblique asymptote equation is :
y=x-6