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प्रश्न
If 2 log x + 1 = log 360, find: log (3 x2 - 8)
उत्तर
log (3 x2 - 8)
2logx + 1 = log360
⇒ logx2 + log10 = log360
⇒ log(10x2) = log360
⇒ 10x2 = 360
⇒ x2 = `(360)/(10)` = 36
⇒ x = `sqrt(36)` = ±6
As negative value is rejected,
∴ x = 6
∴ log (3 x2 - 8)
= log{3(6)2 - 8}
= log(108 - 8)
= log100
= log102
= 2log10
= 2 x 1
= 2.
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