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.
If we have vertical asymptotes at x = 1 and x = 2.....the denominator must be
( x -1) ( x - 2) = x^2 -3x + 2
Therefore
x^2 - 3x + 2 = x^2 + ax + b
a = -3 b = 2
a + b = -1
