Can't I solve these using my calculator?

If not, can you help me get started? I'm drawing a total blank. Thanks!! :eek:

4^x=1/256

and

10^log(3x)=4

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- Nov 18th 2007, 12:24 PMcrazydaizy78logarithms/calculator/solving
Can't I solve these using my calculator?

If not, can you help me get started? I'm drawing a total blank. Thanks!! :eek:

4^x=1/256

and

10^log(3x)=4 - Nov 18th 2007, 01:28 PMtopsquark

It helps if you know that . Then

so x = -4.

To do this if you don't know that little fact:

<-- If you use or ln here then you don't have to use the change of base formula a little further on.

Now let's say you still haven't seen that . Use the change of base formula to change the base to e (or 10 if you desire):

So we have:

which you can plug into your calculator and get that x = -4.

-Dan - Nov 18th 2007, 01:30 PMtopsquark