College

Which logarithmic equation is equivalent to [tex]$2^7=128$[/tex]?

A. [tex]\log_7 2=128[/tex]
B. [tex]\log_2 7=128[/tex]
C. [tex]\log_7 128=2[/tex]
D. [tex]\log_2 128=7[/tex]

Answer :

To determine which logarithmic equation is equivalent to the expression [tex]\(2^7 = 128\)[/tex], let's first understand the relationship between exponential and logarithmic forms. When you have an exponential equation of the form [tex]\(a^b = c\)[/tex], it can be rewritten in its logarithmic form as [tex]\(\log_a(c) = b\)[/tex].

Let's apply this to [tex]\(2^7 = 128\)[/tex]:

1. Base (a): The base here is 2.
2. Exponent (b): The exponent is 7.
3. Result (c): The result is 128.

Using the logarithmic form [tex]\(\log_a(c) = b\)[/tex], substitute the values we know:

[tex]\[
\log_2(128) = 7
\][/tex]

Now compare this with the given options:

- a) [tex]\(\log_7 2 = 128\)[/tex]
- b) [tex]\(\log_2 7 = 128\)[/tex]
- c) [tex]\(\log_7 128 = 2\)[/tex]
- d) [tex]\(\log_2 128 = 7\)[/tex]

As we can see, option d) [tex]\(\log_2 128 = 7\)[/tex] matches our derived logarithmic equation perfectly. Therefore, the correct answer is:

d) [tex]\(\log_2 128 = 7\)[/tex]