Question

Use the following equation:
log2x + log2(x – 7) = 3

The second step would be to:
Select one:
a. Divide both sides by 3 to simplify.
b. Re-write the equation using the definition of logarithms.
c. Add (x – 7) to both sides to simplify.
d. Either A or C

Answer 1

Do you know your log rules for solving?

Answer 2

I am doing this....

\(\normalsize\color{black}{ \log_2x + \log_2(x – 7) = 3}\)

\(\normalsize\color{black}{ \log_2x + \log_2(x – 7) = 3\log_22}\)

\(\normalsize\color{black}{ \log_2x + \log_2(x – 7) = \log_22^3}\)

\(\normalsize\color{black}{ \log_2x + \log_2(x – 7) = \log_29}\)

\(\normalsize\color{black}{ \log_2x(x – 7) = \log_29}\)

\(\normalsize\color{black}{ \log_2x^2-7x= \log_29}\)

\(\normalsize\color{black}{ x^2-7x=9}\) .....

Answer 3

convert to base 2, and equalize.

Answer 4

I hate this type of questions "what would be your second step and why" man... just post a solution :P

Answer 5

how do you get \[\3log_{3}\]

Answer 6

I multiplied by log(2)2, because log(number)number =1 for every number, besides when
number=1

Answer 7

and not \(\normalsize\color{red}{ \log_3}\) but \(\normalsize\color{black}{ \log_2}\)

Answer 8

i thought i put 2 sorry

Answer 9

Yeah I realized.

Answer 10

I can't say what the second step is, it depends on the first step, doesn't it ?

Answer 11

yea it depends what you do first i would think it is D

Answer 12

It is not, and none of the options that it includes for the first step :)

Answer 13

your first step is ??

Answer 14

Hint: ` log(a)+log(b) = log ( a × b ) `

Answer 15

take the log of each side?\

Answer 16

you already have the side in logs .... I gave you everything to figure it out.