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 `

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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

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