OwlEyes
Which of the following is the solution to the equation 25(z + 2) = 125 ?
z = 5.5
z = 3.5
z = -2.5
z = -0.5
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mahmit2012
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|dw:1337048774351:dw|
OwlEyes
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3 isnt an option
thejoshfish
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just solve the equation.. it's not that hard.
OwlEyes
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is 3.5?
mahmit2012
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|dw:1337049106838:dw|
thejoshfish
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test it.
3.5+2=5.5
5.5(25)=137
so no
sputnik
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I would start by multiplying the equation out.
25z + 50 = 125.
Then I would solve for z.
First isolate it:
25z = 75
And then divide by 25.
z = 3.
OwlEyes
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3 is not an option
thejoshfish
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well your math book is wrong then.
OwlEyes
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No i wrote it wrong!! lol
Its:
25^(z+2)=125
sputnik
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You need to take the log of both sides then solve for z..
OwlEyes
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how do i do that?
sputnik
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It looks like this:
2 * ln(5) * z + 4 * ln(5) = 3 * ln(5)
OwlEyes
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I dont know what that means??
sputnik
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And to finish it up as in actually compute it you need to use a calculator because the decimals are messy.
3.21 * z + 6.43 = 4.82
And solve for z.
sputnik
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You will get z = -0.5.
Is that one of the options?
OwlEyes
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Yepp:)) Thanks sooo much!
sputnik
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No prob. Thanks for the medal.
And for the logs, on the right hand side, 125 = 5 ^ 3. so it equals 3 * ln(5). The exponent out front and the log of what the exponent worked on.
OwlEyes
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Ohhh gotcha! Thanks again and you deserve it:)