234k views
3 votes

1 + log_(2)(x - 2) = log_(2)x

2 Answers

2 votes

Move all the logarithms on the left hand side, and all the constants on the other:


\log_2(x-2) - \log_2(x) = -1

Use the rule of logarithms


\log_a(b) - \log_a(c) = \log_a\left((b)/(c)\right)

To rewrite the equation as


\log_2\left((x-2)/(x)\right) = -1

Evaluate 2 to the power of each side:


(x-2)/(x) = 2^(-1) = (1)/(2)

Multiply both sides by 2x:


2(x-2) = x \iff 2x-4 = x \iff x = 4

User Paul Ogilvie
by
6.5k points
3 votes

1 + log₂(x - 2) = log₂(x)

1 = log₂(x) - log₂(x - 2)

1 = log₂
(x)/(x - 2)

2¹ =
(x)/(x - 2)

2(x - 2) = x

2x - 4 = x

-4 = -x

4 = x

Answer: 4

User BHF
by
6.4k points
Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.