š Precalculus Exponents And Logarithms
Recommended: 30ā40 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 à 2 à 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 à 2³?
A) $2^5$ B) $2^6$ C) $4^5$ D) $4^6$ E) $8^5$
Answer & Solution
Answer: A
2² Ć 2³ = 2^(2+3) = 2āµ.
4.
Tags: Logarithm Rules Ā· Easy Ā· source: Original (AMC-style)
What is logā(9) + logā(3)?
A) $2$ B) $3$ C) $4$ D) $5$ E) $6$
Answer & Solution
Answer: B
logā(9) + logā(3) = logā(9 Ć 3) = logā(27) = 3.
5.
Tags: Negative Exponents Ā· Easy Ā· source: Original (AMC-style)
What is 2ā»Ā²?
A) $-4$ B) $-2$ C) $\frac{1}{4}$ D) $\frac{1}{2}$ E) $4$
Answer & Solution
Answer: C
2ā»Ā² = 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) = ā4 = 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 = 2ā“ = 16.
10.
Tags: Change of Base Ā· Medium Ā· source: Original (AMC-style)
What is logā(64)?
A) $1$ B) $2$ C) $3$ D) $4$ E) $8$
Answer & Solution
Answer: B
logā(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^(3Ć2) = 2ā¶.
12.
Tags: Complex Logarithms Ā· Hard Ā· source: Original (AMC-style)
What is logā(3) + logā(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
| # | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Ans | C | B | A | B | C | A | A | B | C | B | B | E |