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w86lynn
Feb 26, 2007, 05:31 PM
I'm having trouble with these problems if someone could help me that would be great.

2^(3x-5)=4
27^(7x-3)=3^(20x+19)
log X + log 4= log 5

cool_dude
Feb 26, 2007, 09:19 PM
you just need to know some rules(properties) of logarithms and you can solve it.

1) 2^3x-5 = 4
3x-5log2 = log 4 (pay attention to this property. You take the log of both sides and
3x = log 4 + 5log2 exponents come down)
x = (log 4 + 5log2) / 3

2) 27^7x-3 = 3^20x+19
use the same property as in question 1 and you'll get it. Post your answer if you want me to verify it for you

3)logx + log4 = log5
this is another property.
log x = log 5 - log 4
10 ^ log5-log4 = x (this is another property)