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

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 `

shaalaa.com

Interchanging Logarithmic and Exponential Forms

Is there an error in this question or solution?

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

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

Express the following in exponential form :
log₁₀0.01 = - 2

Express the following in exponential form : log₁₀1 = 0

Find the logarithm of : `1/81` to the base 27

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

Find x, if : log₃ x = 0

Find x, if : log₉243 = x

Evaluate : log₁₀0.01

Evaluate : log₅ 1

If log_am = n, express a^{n - 1} in terms of a and m.

State true or false in the following:
If log ₂ 8 = 3, then log ₈ 2 = `(1)/(3)`