check!

here is the question:
log5(x-4)= log7x solve for x.

These are just base 10 logs.
log100 = 2
This equation has the same format as log 40 = log (2x20)

Since both sides have log base 10, you divide by log base 10 and end up with 5(x-4) = 7x, so 5x -20 =7x x=-10


One doesn't exactly "divide by base 10".

log5(x-4)= log7x solve for x.
take each side as exponents to the base 10, or
10^(log5(x-4))= 10^(log7x)
then
5(x-4) = 7x
and x= 10
check...
log (5(-14)= log -70
log (-70)=log(-70) and it checks

  1. 👍
  2. 👎
  3. 👁

Respond to this Question

First Name

Your Response

Similar Questions

  1. Math

    Log5(3÷5)+3log5(15÷2)-log5(81÷8)

  2. Algebra II

    Use log5(2)=0.4307 and log5(3)=0.6826 to approximate the value of log5=54. According to the example in my book I would divide 0.6826 by 0.4307 and the answer is 1.5848 but this is not one of the answers given. My choices are: a)

  3. Math

    Simplify (Log75+log9+log5)÷(log5+log45)

  4. mathematics

    Given that log5 3=0.683 and log5 7=1.209.without using calculator,evaluate (a) log5 1.4 b)log7 75 c) log3 125

  1. algebra 2

    Use change of base to rewrite the expression, log5 16 When I solved this, I got log10 16 / log10 5 But when checking it on mathway I got log 16 / log 5 Could someone explain this?

  2. algebra 2

    Logs are stacked 7 rows high. The top row has 15 logs, the second row has 18 logs, and the third row has 21 logs. This pattern continues similarly. What is the total number of logs in the stack?

  3. Pre Calculs

    The pH of a chemical solution is given by the formula pH = -log10 [H+] where [H+] is the concentration of hydrogen ions in moles per liter. Values of pH range from 0 (acidic) to 14 (alkaline). (a) what is the pH of the solution

  4. precalculus

    solve the logarithmic equation . express solution in exact form log5(x-9)+log5(x+4)=1+log5(x-5)

  1. LOGARITHMS

    HI THE QUESTION STATES THAT ONE SHOULD CALCULATE THE LOGS WITHOUT THE USE OF A CALCULATOR...OKAY MY PROBLEM IS THIS... 2 3 2log 8 + 2log 8 what should i do? i had come to the piont of... 4 5 log 8 + log 8 But what's to do now i

  2. Math

    Logs are stacked up in apile as shown in the figure. The top row has 15 logs and the bottom row has 21 logs. How many logs are in the stack? a1= 1+14=15 an= 7+14=21 s1=(n/2)(a1+an) (n/2)(15+21) = 18 How do I figure out the n?

  3. maths

    I need explanation to this question.solve 48 base12 multiply by 15 base12.i can solve it by first converting to base ten and back to base 12,but i need to be able to solve directly in base12.Thanks

  4. precalc help

    Find the exact value without a calc 1. log base 3 of 8 times log base 8 of 9. I started by changing both bases to 10 but don't know what to do from there. 2. e ^ log base e^2^9. I hope that isnt confusing. My teacher said we are

You can view more similar questions or ask a new question.