If f(x) = ln(x^2 - 3x + 2), what is the domain of f in interval notation?
Correct: A
For ln(u) to be defined, we need u > 0. So we need x^2 - 3x + 2 > 0. Factor: (x - 1)(x - 2) > 0. The critical points are x = 1 and x = 2. Testing intervals: For x < 1, both factors are negative, so product is positive. For 1 < x < 2, (x-1) > 0 and (x-2) < 0, so product is negative. For x > 2, both factors are positive, so product is positive. Therefore x^2 - 3x + 2 > 0 when x < 1 or x > 2. The domain is (-∞, 1) ∪ (2, ∞). The correct answer is A.