# Log question with negative exponent

• Dec 13th 2009, 01:02 PM
toony
Log question with negative exponent
4^x + 6(4^-x) = 5

• Dec 13th 2009, 01:10 PM
Plato
Quote:

Originally Posted by toony
4^x + 6(4^-x) = 5

$4^x+6\cdot 4^{-x}=5$ is same as $4^{2x}-5\cdot 4^x +6 = 0$ (we multiply by $4^x$).

Can you solve $z^2-5z+6=0?$
If so let each of those $z's$ equal $4^x$ and solve.
• Dec 13th 2009, 01:23 PM
toony
Wow thanks. didnt notice that !(Doh)