Answered

Solve 9^x + 4 = 11 for x using the change of base formula log base b of y equals log y over log b.
A.) −3.094
B.) −2.909
C.) 4.916
D.) 5.091

Answer :

Answer:

If you meant [tex]9^x+4=11[/tex], then the answer is approximately 0.866.

If you meant [tex]9^{x+4}=11[/tex], then the answer is approximately -2.909 which looks like what you meant based on the choices.

Step-by-step explanation:

[tex]9^x+4=11[/tex]

First step is to get the exponential part by itself. The part that has the variable exponent which is the [tex]9^x[/tex] term.

To do this we need to subtract 4 on both sides:

[tex]9^x=11-4[/tex]

Simplify:

[tex]9^x=7[/tex]

The equivalent logarithmic form is:

[tex]\log_9(7)=x[/tex]

I always say to myself the logarithm is the exponent that is how I know what to put opposite the side containing the log.

Anyways if you don't have options for computing [tex]\log_b(a)[/tex] in your calculator you need to use the change of base formula.

[tex]\frac{\log(7)}{\log(9)}=x[/tex]

So [tex]x \approx 0.8856[/tex]

I don't see this as a choice so maybe you actually meant the following equation:

[tex]9^{x+4}=11[/tex]

Let's see if this is the correct interpretation.

So the exponential part is already isolated.

So we just need to put in the equivalent logarithmic form:

[tex]\log_9(11)=x+4[/tex]

Now we subtract 4 on both sides:

[tex]\log_9(11)-4=x[/tex]

Again if you don't have the option for computing [tex]\log_b(a)[/tex] in your calculator, you will have to use the change of base formula:

[tex]\frac{\log(11)}{\log(9)}-4=x[/tex]

[tex]x \approx -2.909[/tex]

i know im late, but the answer is b. -2.909 :)

Other Questions