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WAEC Mathematics 2016 Paper

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Question : 32

Total: 49

If log₂(3x - 1) = 5, find x.

2.00
3.67
8.67
11

Solution:

Concept:

The equation

\log_2(3x - 1) = 5

can be rewritten in exponential form: if

\log_b y = c

, then

y = b^c

.

Explanation:

Start with

\log_2(3x - 1) = 5

.

Convert the logarithm to exponential form:

3x - 1 = 2^5

Evaluate the power:

3x - 1 = 32

Add

1

to both sides:

3x = 33

Divide both sides by

3

:

x = \frac{33}{3}

x = 11

Answer:

x = 11

, which is option D.

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