Logarithms

Write in logarithmic form.
2^-4 = ¹/₁₆

• log₂(¹/₁₆) = -4
• log_-4(¹/₁₆) = 2
• log _-4 2 = ¹/₁₆
• log₂(-4) = ¹/₁₆

Write in exponential form.
log₂32 = 5

• 2^-5 = 32
• 2³² = 5
• 2⁵ = 32
• 32⁵ = 2

Rewrite 3⁴ = 81 in logarithmic form.

• log₃4 = 81
• log₈₁3 = 4
• log₃81 = 4
• log₄81 = 3

Solve for x
5^x = 17

• x = log₁₇5
• x = log 5 + log 17
• x = log₅17
• x = (log 5)/(log 17)

Rewrite in exponential form:
ln(2) = x

• 2^x = 10
• 10² = x
• e^x = 2
• e² = x

Rewrite e^x = 9 using a logarithm

• ln x = 9

• ln 9 = x

• log_x e = 9

• log₉ x = e

Rewrite log₂8 = 3 in exponential form

• 2⁸ = 3

• 2³ = 8

• 3² = 8

• 8³ = 2

Solve for x:
log_x 25 = 2

• 5
• -5
• 1/5
• -1/5

Write in log form then solve for x.

3^x = 27

• 2
• 4
• 3
• 5

Evaluate.
log₃81

• 4
• ¹/₄
• -4
• -¹/₄