If Log (X2 - 21) = 2, Show that X = ± 11.

If log (x² - 21) = 2, show that x = ± 11.

Sum

log (x² - 21 ) = 2
⇒ x²- 21 = 10^2
⇒ x² - 21 = 100
⇒ x²= 121
⇒ x = `+- 11 `

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Interchanging Logarithmic and Exponential Forms

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Chapter 8: Logarithms - Exercise 8 (A) [Page 104]

Chapter 8 Logarithms
Exercise 8 (A) | Q 12 | Page 104

Express the following in logarithmic form:
10^–3 = 0.001

Express the following in logarithmic form:

`3^-2 = 1/9`

Express the following in exponential form : log₈0.125 = -1

Solve for x : log₁₀ x = -2.

Find the logarithm of : 0.1 to the base 10

Find the logarithm of : 0.125 to the base 2

Find the logarithm of : `1/16` to the base 4

State, true or false : If log₁₀ x = a, then 10^x = a.

State, true or false : log₂ 8 = 3 and log₈ = 2 = `1/3`

Evaluate : log₁₆ 8