# Logarithmic eqautions

1. Jan 6, 2012

### bluff_boy

Having problems with these questions, what's putting me off is for example the first question, if the numbers 9 and 5 were the same I think I could do it. Do I have to get them to the same number or do I just multiply them?

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2. Jan 6, 2012

### micromass

For (1). Take log of both sides and use logarithm rules.

That's about all the help I'm giving you right now. You make an effort now.

3. Jan 6, 2012

### eumyang

For (ii), multiply both sides by et. Let w = et, and rewrite the equation in terms of w. What does the resulting equation look like now?

4. Jan 6, 2012

### Ray Vickson

(i) lhs= 125*[9^3 *5^2]^x = 125* 18225^x
rhs = 3^3*2^4/5^2 *[3^4/2/5^3]^x = (432/25)(81/250)^x.
Thus, [18225*250/81]^x = (432/25)/125.

(ii) Put x = exp(t) and see what you get.

(iii) Put x = ln(i+2). First you need to decide if $\ln(i+2)^6$ means $\ln [(i+2)^6]$ or $[ \ln (i+2) ]^6 .$

RGV