Let
f(x)=x2−4x+3x2−9.
Answer the following questions.
a. (i) Find all real numbers where f is not defined.
b. (ii) Determine the limit of f(x), if it exists, at each point obtained in part (i).
c. (iii) Classify each point of non-definition as giving rise to a removable discontinuity or an infinite discontinuity.
d. (iv) For every removable discontinuity, find the value that should be assigned to f at that point so that the function becomes continuous there.