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Mathematics 18 Online
OpenStudy (anonymous):

Solve each equation or inequality. CLICK

OpenStudy (anonymous):

\[5^{X}=4^{x+3}\]

OpenStudy (whpalmer4):

Do you remember the property of logarithms that \(\log a^x = x \log a\)? That should give you a clue as to how to proceed...

OpenStudy (abb0t):

log both sides.

OpenStudy (anonymous):

in depth explanation please ?

OpenStudy (abb0t):

@whpalmer4 gave you a pretty good explanation. Lol

OpenStudy (whpalmer4):

\[\log 5^x = \log 4^{x+3}\]\[x \log 5 = (x+3) \log 4\] Solve for \(x\)

OpenStudy (anonymous):

i dont know what to do from there honestly.

OpenStudy (abb0t):

What do YOU think your next step should be? You won't understand unless you try it and make mistakes first.

OpenStudy (anonymous):

divide both sides by x and you're left with log 5= 3 log 4 ?

OpenStudy (abb0t):

I like your thinking, but not quite. Since you are solving for "x". It must be in the form: x = ____ hence, you can't cancel out x. First step is to distribute the log(4) across the parenthesis.

OpenStudy (abb0t):

put all your constants on one side, and put the x's on the other side.

OpenStudy (anonymous):

x^2= 3log 4 x 3 log 5 ?

OpenStudy (abb0t):

No. I don't know where you got the x squared, but you should get this: \[xlog(5) = xlog(4)+3\log(4)\] Now, notice that you have TWO log's with x's. Which means that you can subtract it! \[xlog(5)-xlog(4) = 3\log(4)\] now, what do you think is the next step? [HINT: you have to factor OUT something...]

OpenStudy (anonymous):

factor out the x ?

OpenStudy (abb0t):

Correct. Now you'll have: \[x[\log(5)-\log(4)]=3\log(4)\] now, if you want to solve for "x". What do you think you should do now to get x by itself?

OpenStudy (anonymous):

divide ?

OpenStudy (abb0t):

Great.

OpenStudy (anonymous):

....

OpenStudy (abb0t):

What did you divide by? If you divided correctly, you should see that you have now arrived at your answer.

OpenStudy (anonymous):

divide both sides by 4 ?

OpenStudy (abb0t):

No. Why would you divide by 4? You would divide everything EXCEPT x. yOU ARE Trying to solve for x.

OpenStudy (abb0t):

\[x = \frac{ 3\log(4) }{ \log(5)-\log(4) }\]

OpenStudy (anonymous):

okay, thats my final answer ? i wouldnt simplify anything ?

OpenStudy (abb0t):

yes...

OpenStudy (anonymous):

thank you !

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