If f(x) = (x + 4)/(x^2 + ax + b), and f(x) has two vertical asymptotes at x = 1 and x = 2, find the sum of a and b.

In this problem, any x value that makes the denominator = 0 will produce an asymptote at that x value

We can write the denominator as

(x - 1) ( x - 2) =

x^2 - 3x + 2

a = -3 b = 2 their sum is -1