SOLUTION: 3^2x +3^x = 12

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Question 860626: 3^2x +3^x = 12
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
3^2x +3^x = 12
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Sub u for 3^x
u%5E2+%2B+u+-+12+=+0
(u+4)*(u-3) = 0
u = -4 --> 3^x = -4 extraneous, ignore
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u = 3 --> 3^x = 3
x = 1