Help!

Feb 20, 2007 17:31

Im in high school honors precalc, so this question should be fairly easy for some of you.

how do i solve

8^(x squared - 2x) = 1/2 ?

or

3^(x cubed) = 9 ^ x.

im so lost.. :(

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Comments 5

filosophicphool February 20 2007, 22:43:21 UTC
do you remember your logarithm rules?

Also, if you look downward in the community, you'll see a bunch of posts about logarithms. those posts should point you in the right direction

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maynard_lover February 20 2007, 22:45:14 UTC
Notice that 8 is the same as 2^3. Also notice that 1/2 is 2^-1. When we have bases that are the same, we can set the exponents equal to one another.

So, referring to the first one, 2^3(x^2 - 2x) = 2^-1. So, multiplying the 3 through, we get 3x^2 - 6x = -1, or 3x^2 - 6x + 1 = 0. Solve as you normally would a quadratic. (Quadratic formula, complete the square, etc.)

Try the above with the second problem also. Make the bases the same is the key.

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filosophicphool February 21 2007, 00:45:46 UTC
haha, i didn't even think of that. but i guess thats easy, and doesn't use logs...

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projectinfamy February 21 2007, 02:56:37 UTC
random i know, but
where is your icon from?

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magdaz February 21 2007, 14:15:58 UTC
heh, yeah it's making the bases the same that should work.

Haha, and that is a pretty cool icon, especially since 'Here comes the sun' is a song by the Beatles, and I'm going to listen to it now. XD

Niiiiiiice. =D

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