FactoringMediumQuestion 240007
Question
lim(x→3) (x³ − 27)/(x − 3) equals:
- A27Correct
- B9
- C3
- D0
Correct answer
27
Explanation
Using the identity aⁿ − bⁿ = (a−b)(aⁿ⁻¹ + aⁿ⁻²b + ... + bⁿ⁻¹): x³ − 27 = (x−3)(x² + 3x + 9). Cancel (x−3): limit = x² + 3x + 9 at x = 3 = 9 + 9 + 9 = 27.