apply log
xlog8/xlog8=(x+1)log16/xlog9
1=(x+1)log16/xlog9
xlog9=xlog16+log16
x(log9-log16)=log16 => x=log16/log9-log16 => x=- 0,25
2006-09-24 21:54:42
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answer #1
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answered by Λиδѓεy™ 6
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4^2x / 8^x = 16^(x + 1)/3^2x
Change 4,8 and 16 to a power of 2
2^4x / 2^3x = 2^(4x + 4)/3^2x
We "shift" 3^2x to the left by cross-multiplying and "shift" the powers of 2 to the right side
3^2x = 2^(4x + 4) · 2^3x / 2^4x
Using exponent properties,
3^2x = 2^(4x + 4 + 3x - 4x)
Thus,
3^2x = 2^(3x + 4)
Get the ln of both sides:
ln 3^2x = ln 2^(3x + 4)
Thus,
2x ln 3 = (3x + 4) ln 2
Distribute ln 2
2x ln 3 = 3x ln 2 + 4 ln 2
Thus,
2x ln 3 - 3x ln 2 = 4 ln 2
Factor x
x (2 ln 3 - 3 ln 2) = 4 ln 2
and
x = 4 ln 2/(2 ln 3 - 3 ln 2)
We combine the ln's into one ln (logarithm)
x = ln 2^4/(ln 3^2 - ln 2^3)
x = ln 16/(ln 9/8)
x = log_9/8 16 or
x = 4 log_9/8 2
The answer is:
x = 4 times the logarithm of 2 to the base 9/8.
or approximately 23.5398. Try substituting. You will get a good result!
Try
^_^
2006-09-25 08:37:26
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answer #2
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answered by kevin! 5
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x= 8/5
2006-09-25 05:12:53
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answer #3
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answered by sartaj.alam 1
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Simplify 4^(2x)/8^(x) = 2^(4x)/2^(3x) = 2^x. Then
(2^x)*(3^2x) = 16^(x+1) and
x*log2 + 2x*log3 = (x+1)*log16
Now crank up the calculator and solve it for x âº
Doug
2006-09-25 05:10:57
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answer #4
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answered by doug_donaghue 7
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x = (4ln2) / ln(9/8) <--- that's the answer.
Try to express 4, 8 and 16 as a power of 2.
Then, use the PROPERTIES of LN ( natural logarithms) in order to solve for x. please check it out.
2006-09-25 05:02:51
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answer #5
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answered by Hanz 2
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the previous guy's answer is correct. x=8/5
2006-09-25 05:14:50
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answer #6
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answered by an0nymu$ 1
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x=ln(16)/(ln9-ln 8)
2006-09-25 06:01:45
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answer #7
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answered by Anonymous
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2xln4-xln8=xln16+ln16-2xln3
x(2ln4-ln8-ln16+2ln3)=ln16
x(ln16-ln8-ln16+ln9)=ln16
xln(9/8)=ln16
x=ln16/ln(9/8)
x=23.54
2006-09-25 05:25:59
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answer #8
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answered by Helmut 7
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