Question

If 2 log x + 1 = log 360, find: log(2 x -2)

Answer 1

log(2 x -2)
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 (2x - 2)
= log(2.6 - 2)
= log 10
= 1.