šŸ“˜ Precalculus Exponents And Logarithms

Recommended: 30–40 minutes. No calculator.

Problems

1.

Tags: Basic Exponent Ā· Easy Ā· source: Original (AMC-style)

What is 2³?

A) $4$ B) $6$ C) $8$ D) $9$ E) $12$

Answer & Solution

Answer: C

2³ = 2 Ɨ 2 Ɨ 2 = 8.

2.

Tags: Basic Logarithm Ā· Easy Ā· source: Original (AMC-style)

What is logā‚‚(8)?

A) $2$ B) $3$ C) $4$ D) $8$ E) $16$

Answer & Solution

Answer: B

logā‚‚(8) = 3 because 2³ = 8.

3.

Tags: Exponent Rules Ā· Easy Ā· source: Original (AMC-style)

What is 2² Ɨ 2³?

A) $2^5$ B) $2^6$ C) $4^5$ D) $4^6$ E) $8^5$

Answer & Solution

Answer: A

2² Ɨ 2³ = 2^(2+3) = 2⁵.

4.

Tags: Logarithm Rules Ā· Easy Ā· source: Original (AMC-style)

What is logā‚ƒ(9) + logā‚ƒ(3)?

A) $2$ B) $3$ C) $4$ D) $5$ E) $6$

Answer & Solution

Answer: B

logā‚ƒ(9) + logā‚ƒ(3) = logā‚ƒ(9 Ɨ 3) = logā‚ƒ(27) = 3.

5.

Tags: Negative Exponents Ā· Easy Ā· source: Original (AMC-style)

What is 2⁻²?

A) $-4$ B) $-2$ C) $\frac{1}{4}$ D) $\frac{1}{2}$ E) $4$

Answer & Solution

Answer: C

2⁻² = 1/2² = 1/4.

6.

Tags: Fractional Exponents Ā· Easy Ā· source: Original (AMC-style)

What is 4^(1/2)?

A) $2$ B) $4$ C) $8$ D) $16$ E) $32$

Answer & Solution

Answer: A

4^(1/2) = √4 = 2.

7.

Tags: Logarithm Properties Ā· Medium Ā· source: Original (AMC-style)

What is logā‚…(25) - logā‚…(5)?

A) $1$ B) $2$ C) $3$ D) $4$ E) $5$

Answer & Solution

Answer: A

logā‚…(25) - logā‚…(5) = logā‚…(25/5) = logā‚…(5) = 1.

8.

Tags: Exponential Equations Ā· Medium Ā· source: Original (AMC-style)

If 3Ė£ = 27, what is x?

A) $2$ B) $3$ C) $4$ D) $5$ E) $6$

Answer & Solution

Answer: B

3ˣ = 27 = 3³, so x = 3.

9.

Tags: Logarithmic Equations Ā· Medium Ā· source: Original (AMC-style)

If logā‚‚(x) = 4, what is x?

A) $8$ B) $12$ C) $16$ D) $20$ E) $24$

Answer & Solution

Answer: C

logā‚‚(x) = 4 means x = 2⁓ = 16.

10.

Tags: Change of Base Ā· Medium Ā· source: Original (AMC-style)

What is logā‚ˆ(64)?

A) $1$ B) $2$ C) $3$ D) $4$ E) $8$

Answer & Solution

Answer: B

logā‚ˆ(64) = 2 because 8² = 64.

11.

Tags: Advanced Exponents Ā· Hard Ā· source: Original (AMC-style)

What is (2³)²?

A) $2^5$ B) $2^6$ C) $4^3$ D) $8^2$ E) $64$

Answer & Solution

Answer: B

(2³)² = 2^(3Ɨ2) = 2⁶.

12.

Tags: Complex Logarithms Ā· Hard Ā· source: Original (AMC-style)

What is logā‚‚(3) + logā‚ƒ(2)?

A) $1$ B) $2$ C) $\log_6(6)$ D) $\log_6(12)$ E) Cannot be simplified

Answer & Solution

Answer: E

This expression cannot be simplified using standard logarithm properties.

Answer Key

#123456789101112
AnsCBABCAABCBBE

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