using indices only, and the substitution y=2^x , solve the equation:

2^2x - 6.2^x + 8 = 0

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- Mar 13th 2011, 01:06 AMjakethasnakeIndices Problem!
using indices only, and the substitution y=2^x , solve the equation:

2^2x - 6.2^x + 8 = 0 - Mar 13th 2011, 01:18 AMUnknown008
Okay, could you perform the substitution?

- Mar 13th 2011, 01:23 AMProve It
Maybe it will help if you rewrite your equation as

$\displaystyle \displaystyle \left(2^x\right)^2 - 6\cdot 2^x + 8 = 0$... - Mar 13th 2011, 01:28 AMjakethasnake
im lost as to where the substitution goes? and the question is written exactly as shown out of previous exam paper.

- Mar 13th 2011, 03:31 AMHallsofIvy
Look at Prove It's response. See those "$\displaystyle 2^x$"s? Replace

**those**with y. - Mar 13th 2011, 03:34 AMProve It