SOLUTION: Could you help me solve this please? a) {{{9^(7-3x) =5}}} b) {{{log0.135}}} is the answer -0.8696 c) {{{log(7,22)}}} is the answer: 1.588 Thank you so much

Algebra ->  Quadratic Equations and Parabolas -> SOLUTION: Could you help me solve this please? a) {{{9^(7-3x) =5}}} b) {{{log0.135}}} is the answer -0.8696 c) {{{log(7,22)}}} is the answer: 1.588 Thank you so much      Log On


   



Question 1043210: Could you help me solve this please?
a) 9%5E%287-3x%29+=5
b) log0.135
is the answer -0.8696
c) log%287%2C22%29
is the answer: 1.588
Thank you so much

Found 2 solutions by stanbon, ikleyn:
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Could you help me solve this please?
a) 9^(7-3x) =5
(7-3x)*log(9) = log(5)
7-3x = log(5)/log(9)
7-3x = 0.7325
3x = 6.2675
x = 2.0892
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b) log0.135
is the answer -0.8696
Yes, or -0.8697 if you round off
-----------------------------------

c) log(7,22) = log7(22) = log(22)/log(7) = 1.588
is the answer: 1.588
---------------------
Cheers,
Stan H.
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Answer by ikleyn(52777) About Me  (Show Source):
You can put this solution on YOUR website!
Could you help me solve this please?

a) 9%5E%287-3x%29+=5

b) log0.135       <<<--- To solve it, apply your calculator or computer . . .  Or apply special tables for logarithms, if you have it. 
                               It is the only way in this case.  // The other way is to expand it in series, but nobody will do it in our days.
                               When you ask other people to do it for you, you simply shift/move your work to their shoulders. 
                               It is not a job for tutors. It is your work.
is the answer -0.8696

c) log%287%2C22%29      <<<--- Apply the formula for the base change for logarithms,  log%28a%2Cx%29+=+log%28b%2Cx%29%2Flog%28b%2Ca%29,  and you will get log%287%2C22%29 = log%28%2822%29%29%2Flog%28%287%29%29 with decimal logarithms.

                        See the lesson Change of Base Formula for logarithms in this site.
                              
is the answer: 1.588

Thank you so much

On logarithms, read the lessons
    - WHAT IS the logarithm,
    - Properties of the logarithm,
    - Change of Base Formula for logarithms,
    - Solving logarithmic equations,
    - Using logarithms to solve real world problems
in this site.

You also have free of charge Online textbook on Algebra-I in this site
    - ALGEBRA-I - YOUR ONLINE TEXTBOOK
in this site.