Mathematics
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OpenStudy (anonymous):
The graph of f(x) = 2^x + 4 shifts six units to the right when it is replaced with the graph of f(x) = 2^x - k. What is the value of k?
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OpenStudy (anonymous):
2
4
6
10
OpenStudy (anonymous):
@jim_thompson5910 do you think you could help?
jimthompson5910 (jim_thompson5910):
the x+4 is all in the exponent?
OpenStudy (anonymous):
yep
jimthompson5910 (jim_thompson5910):
so is x-k ?
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OpenStudy (anonymous):
yep
jimthompson5910 (jim_thompson5910):
to shift f(x) 6 units to the left, we replace every x with x+6
OpenStudy (anonymous):
ok
OpenStudy (anonymous):
so it would be x+6+4?
jimthompson5910 (jim_thompson5910):
Correct
\[\Large f(x) = 2^{x+4}\]
\[\Large f(x+6) = 2^{x+6+4}\]
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jimthompson5910 (jim_thompson5910):
simplify x+6+4 and compare it to x-k to figure out what k would be
OpenStudy (anonymous):
so it'll be x+10
OpenStudy (anonymous):
so k=10?
jimthompson5910 (jim_thompson5910):
x+10
x-k
k = ???
jimthompson5910 (jim_thompson5910):
it might help to rewrite x+10 as x-(-10)
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OpenStudy (anonymous):
im confused
OpenStudy (anonymous):
wait would it be 10-k?
jimthompson5910 (jim_thompson5910):
\[\Large x + 10\\
\Large x - (-10)\\
\Large x - (\color{red}{-10})\\
\Large x - \color{red}{k}
\]
So k = -10
OpenStudy (anonymous):
but there isnt a -10 as an answer
jimthompson5910 (jim_thompson5910):
oh I went the wrong direction. It's to the right, so x gets replaced with x-6
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OpenStudy (anonymous):
so it would be x+2?
jimthompson5910 (jim_thompson5910):
f(x) = 2^(x+4)
f(x-6) = 2^(x-6+4)
f(x-6) = 2^(x-2)
so k = 2
jimthompson5910 (jim_thompson5910):
x-2 actually
OpenStudy (anonymous):
thank you
OpenStudy (anonymous):
i got it right :D
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OpenStudy (anonymous):
thank you so much
jimthompson5910 (jim_thompson5910):
np