Mathematics
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OpenStudy (anonymous):
Solve for x
(x-2)^-4=625
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OpenStudy (4meisu):
Is this a log question?
OpenStudy (anonymous):
no
OpenStudy (4meisu):
(x-2)^4=625
= (x^4 + 16) = 625
x^4 = 609
x= 5
OpenStudy (anonymous):
I got 7 I am really confused
OpenStudy (anonymous):
that (x-2)^4 is -4 not 4
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OpenStudy (4meisu):
How did you get 7? What's your working?
OpenStudy (anonymous):
(x-2)=625^(1/4)
x-2=5
x=7
OpenStudy (anonymous):
Can someone help me please
OpenStudy (4meisu):
Oh my bad, I forgot to put the negative before the 4. Then yep, 7 is the answer!
OpenStudy (4meisu):
Actually no
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OpenStudy (4meisu):
you're supposed to solve what's in the bracket first.
OpenStudy (4meisu):
you can't bring the ^4 to the other side.
OpenStudy (anonymous):
\[(x-2)^{-4}=625\]
OpenStudy (anonymous):
oh ok but then x=7 is correct
OpenStudy (4meisu):
No it would not be. If x = 7 the answer would be 0.016, not 625.
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OpenStudy (anonymous):
I am really confused
OpenStudy (4meisu):
You have to first solve what's in the brackets. So (x-2) ^-4
OpenStudy (anonymous):
ok got that then I have x^-4 then what
OpenStudy (anonymous):
this \((x-2)^{-4}\) means this \(\frac{1}{(x-2)^4}\)
OpenStudy (anonymous):
you have
\[\frac{1}{(x-2)^4}=625\] so
\[(x-2)^4=\frac{1}{625}\]
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OpenStudy (anonymous):
Yes^, but this means there are real and complex answers.?
OpenStudy (anonymous):
that means
\[x-2=\pm\frac{1}{5}\]
OpenStudy (anonymous):
if
\[x-2=-\frac{1}{5}\] then
\[x=-\frac{1}{5}+2=\frac{9}{5}\] and if
\[x-2=\frac{1}{5}\] then
\[x=\frac{1}{5}+2=\frac{11}{5}\]
OpenStudy (anonymous):
so your two answers are
\[x=\frac{9}{5}\] or
\[x=\frac{11}{5}\]
OpenStudy (anonymous):
and 2 - i/5
2 + i/5 if you want the complex parts