Log₂(2x-18) +log₂ (x-9) = 5

Question

Log₂(2x-18) +log₂ (x-9) = 5

Answer 1

Log₂(2x-18) +log₂ (x-9) = 5

одз х>9

log(a) bc = log(a)b + log(a)c

2x-18=2(x-9)

log(2)2 + log(2)(x-9) + log(2)(x-9) = 5

2log(2)(x-9)=4

log(2)(x-9)=2

x-9=4

x=13

Comments

log(2)2 + log(2)(x-9) + log(2)(x-9) = 5

почему так?

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3 и 4 строка сверху