Question 10 • Precalculus
Factor the denominator: x² − 16 = (x − 4)(x + 4), so for x ≠ −4 the function simplifies to 2(x + 4)/(x − 4). Near x = 4, the numerator is positive, while the denominator approaches 0 from below on the left and from above on the right. Thus the left-hand limit is negative infinity and the right-hand limit is positive infinity, so x = 4 is a vertical asymptote. This matches choice C.
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