Which of the following is a solution to the equation log 4 x + log 4 (x – 3) = 1 ?
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OpenStudy (john_es):
Do you mean,
\[\log_4x+\log_4(x-3)=1\]
OpenStudy (anonymous):
yes
OpenStudy (john_es):
Then use the properties of logarithms,
\[\log_ax+\log_ay=\log_a(xy)\]\[\log_ax=1\Rightarrow x=a\]
\[\log_4 x+\log_4(x-3)=1\Rightarrow \log_4\left(x(x-3)\right)=1\Rightarrow x(x-3)=4\]
And solve for x. Do you understand it and know how to solve it?
OpenStudy (anonymous):
not really
OpenStudy (anonymous):
ohhh i get it now
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OpenStudy (anonymous):
thanks
OpenStudy (john_es):
;), only to check it, the only (good) solution is 4.
OpenStudy (anonymous):
1 over the square root of 8 = 4(m + 3)
OpenStudy (anonymous):
can you help with this too
OpenStudy (john_es):
Do you mean,
\[\frac{1}{\sqrt{8}}=4(m+3)\]
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OpenStudy (anonymous):
yes
OpenStudy (anonymous):
i taught it was 9/4 but its not
OpenStudy (john_es):
Then, it is a matter of solve for m,
\[(m+3)=\frac{1}{4\sqrt{8}}\Rightarrow m=\frac{1}{4\sqrt{8}}-3\]
OpenStudy (john_es):
You can "simplify" a little of express it in various forms,
\[m=\frac{1-24\sqrt{2}}{8\sqrt{2}}=\frac{\sqrt{2}-48}{16}\]
OpenStudy (john_es):
or express it, I mean.
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