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AP Calculus BC Practice Quiz: Determining Limits Using Algebraic Properties of Limits

Written by AP Content Team, Verified for 2026 AP Exams, Last updated: May 2026

Test your understanding with short quizzes. This quiz has 9 questions to check your progress.

Question 1 of 9

If lim(x→c) f(x) = 5 and lim(x→c) g(x) = -2, what is the value of lim(x→c) [f(x) + g(x)]?

All Questions (9)

If lim(x→c) f(x) = 5 and lim(x→c) g(x) = -2, what is the value of lim(x→c) [f(x) + g(x)]?

A) 3

B) -10

C) 7

D) The limit cannot be determined.

Correct Answer: A

According to the limit theorem for sums, the limit of a sum of two functions is the sum of their individual limits. Therefore, lim(x→c) [f(x) + g(x)] = lim(x→c) f(x) + lim(x→c) g(x) = 5 + (-2) = 3.

Given that lim(x→-1) f(x) = 6 and lim(x→-1) g(x) = 3, find lim(x→-1) [2 * f(x) * g(x)].

A) 11

B) 18

C) 36

D) 9

Correct Answer: C

Using the limit theorems for a constant multiple and a product, we have: lim(x→-1) [2 * f(x) * g(x)] = 2 * [lim(x→-1) f(x)] * [lim(x→-1) g(x)] = 2 * 6 * 3 = 36.

Let lim(x→8) p(x) = 12 and lim(x→8) q(x) = 4. What is the value of lim(x→8) [p(x) / q(x)]?

A) 48

B) 3

C) 8

D) The limit does not exist.

Correct Answer: B

The limit theorem for quotients states that the limit of a quotient is the quotient of the limits, provided the limit of the denominator is not zero. Here, lim(x→8) [p(x) / q(x)] = [lim(x→8) p(x)] / [lim(x→8) q(x)] = 12 / 4 = 3.

If lim(x→2) g(x) = 9 and f(x) is a function continuous at x=9 such that f(9) = 5, what is lim(x→2) f(g(x))?

A) 2

B) 9

C) 5

D) The limit cannot be determined.

Correct Answer: C

According to the limit theorem for composite functions, if f is continuous at L and lim(x→c) g(x) = L, then lim(x→c) f(g(x)) = f(L). In this case, c=2 and L=9. Therefore, lim(x→2) f(g(x)) = f(lim(x→2) g(x)) = f(9) = 5.

What is the value of the one-sided limit lim(x→3⁻) (x² - 9) / |x - 3|?

A) 6

B) -6

C) 0

D) The limit does not exist.

Correct Answer: B

To determine this one-sided limit analytically, we consider values of x approaching 3 from the left (x < 3). For x < 3, the term (x - 3) is negative, so |x - 3| = -(x - 3). The expression becomes (x - 3)(x + 3) / -(x - 3). Canceling the (x - 3) terms leaves -(x + 3). The limit is then lim(x→3⁻) -(x + 3) = -(3 + 3) = -6.

If lim(x→a) f(x) = -4 and lim(x→a) g(x) = 5, what is the value of lim(x→a) [3f(x) - g(x)]?

A) -7

B) -17

C) 1

D) 7

Correct Answer: B

This problem requires using the limit theorems for a constant multiple and a difference. lim(x→a) [3f(x) - g(x)] = 3 * [lim(x→a) f(x)] - [lim(x→a) g(x)] = 3 * (-4) - 5 = -12 - 5 = -17.

A function h(x) has the properties that lim(x→5⁺) h(x) = 2 and lim(x→5⁻) h(x) = 2. Which of the following statements must be true?

A) h(5) = 2

B) h(x) is continuous at x = 5.

C) lim(x→5) h(x) = 2

D) The graph of h(x) has a vertical asymptote at x = 5.

Correct Answer: C

The two-sided limit of a function exists if and only if the left-sided and right-sided limits both exist and are equal. Since lim(x→5⁺) h(x) = 2 and lim(x→5⁻) h(x) = 2, we can conclude that lim(x→5) h(x) = 2. We cannot determine the value of h(5) or continuity from the limit alone.

Let f and g be functions such that lim(x→4) f(x) = 9 and lim(x→4) g(x) = -2. Find lim(x→4) [(f(x) * g(x)) / (g(x) + 5)].

A) -18/7

B) -6

C) 6

D) The limit cannot be determined.

Correct Answer: B

This problem requires combining multiple limit theorems. First, find the limit of the numerator using the product rule: lim(x→4) [f(x) * g(x)] = 9 * (-2) = -18. Next, find the limit of the denominator using the sum rule: lim(x→4) [g(x) + 5] = -2 + 5 = 3. Finally, use the quotient rule: lim(x→4) [Numerator / Denominator] = -18 / 3 = -6.

Evaluate lim(x→-2) (x³ + 2x² - 1).

A) -17

B) -1

C) 15

D) -9

Correct Answer: B

The function f(x) = x³ + 2x² - 1 is a polynomial. The limit of a polynomial function can be found by direct substitution, which is a consequence of the limit theorems for sums, differences, and powers. Substituting x = -2 gives: (-2)³ + 2(-2)² - 1 = -8 + 2(4) - 1 = -8 + 8 - 1 = -1.