math

posted by .

still having a hard time understand these? please help?

Logx10 + logx8-logx5=4

Log3256-log327=x

Log 2+ 3log 5-log 25=x

  • math -

    add logs to multiply, subtract to divide
    logx (10*8/5) =4

    logx (16) = 4

    in general base^ logx = x
    so
    16 = x^4
    x = 16^(1/4) = (2*2*2*2)^1/4 = 2

  • math -

    Log3 256-log3 27=x
    same as last question, subtract is divide
    log3 (256/27) = x
    256/27 = 3^x
    I bet you have a typo because 27 is 3^3 but 256 is nothing to the 3 so have to use calculator
    anyway
    9.48 = 3^x
    log10 (9.48) = x log10 (3)
    .9768 = x * .4771
    x = .9768/.4771

  • math -

    base 10 I assume

    Log 2+ 3log 5-log 25=x

    log 2 + log 125 - log 25 = x

    log (250/25) = x

    log 10 = 1 = x

  • math -

    ok so by your previous help i tried to solve this problem
    Log32 56-log32 7=x (log base 32)
    what i did was 57/7=8
    so in log form i got log 32 8=x ( log base 32)
    then changed it to exponential form to 32^x=8
    x= 0.6
    correct?

  • math -

    yes i do have a typo
    Log32 56-log32 7=x
    and my work is above

  • math -

    log 32 (8) = x

    8 = 32^x

    2^3 = 2^5x

    x = 3/5 = 6/10 = 0.6 yes

    I suspected you did not need a calculator :)

  • math -

    It helps if things like 2^3 = 8 and 2^5 = 32 are part of your tool box.

  • math -

    also very common
    3^3 = 27
    5^3 = 125

  • math -

    sorry to bug you but i think this may be the last problem
    2log4 x=3 (log base 4)
    i got log16^x=3
    16^3=x
    x=4096
    right?

  • math -

    log4 (x^2) = 3
    x^2 = 4^3 = 64
    x = 8

  • math -

    log 32 x = 6/10

  • math -

    log 625 3/4 = x

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. math

    write as a single logarithm: -2logbase3(1/x)+(1/3)logbase3(square root of x) please show the steps to solving this. thanx. remember that 1 log (AxB) = log A + Log B (same base) 2 log (A/B) = log A - log B 3 log A^n = n log A use these …
  2. Calculus

    Find the inverse of each relation: y = (0.5)^(x+2) and y = 3log base 2 (x-3) + 2 For the first one I got y=log base 0.5 (x+2)...but the answer in the back of the textbook says that it is not x+2, but x-2. Can someone tell me why it …
  3. Algebra 2

    how do not understand how to do this Log X + Lob (X-3) = 1 I know I do this Log X(X-3)=1 then I do this Log X^(2) - 3X = 1 then I do this 2 Log (X-3X) = 1 then 2 Log (-2X) = 1 then (2 Log (-2X) = 1)(1/2) Log (-2X) = 1/2 then (Log (-2X) …
  4. Mathematics

    Prove that log a, log ar, log ar^2 is an a.p. Is the following below correct?
  5. Math Help Please

    Which of the following expressions is equal to log (x sqrt-y)/z^5 A. log x + log (1/2) + log y– log 5 – log z B. log [x + (1/2)y – 5z] C. log x + (1/2)log y – 5 log z d. [(1/2) log x log y]/(5 log z)
  6. math(Please help)

    1) use the properties of logarithms to simplify the logarithmic expression. log base 10 (9/300) log - log 300 log 9 = 2 log 3 log 300 = log 3 + log 100 = log 3+2 I just do not know how to put these together now!
  7. math

    Logarithm!!! Select all of the following that are true statements: (a) log(2x) = log(2) + log(x) (b) log(3x) = 3 log(x) (c) log(12y) = 2 log(2) + log(3y) (d) log(5y) = log(20y) – log(4) (e) log(x) = log(5x) – log(5) (f) ln(25) …
  8. Precalc

    how to write each expression into a single logarithm. 3log[4]x^(2) + (1/2)log[4]ã(x) the answer is: (25/4)log[4]x steps please
  9. Math

    I'm having a hard time with this problem. The book tells you the answer is 5, but I don't know how they got there. log(x+25)= 1+ log(2x-7)
  10. Math (pre-celc 12)

    Write the expression as a single logarithm: 3log(a)-log(b)-(1/2)log(c) I want to check my answer. I got log(a^3/bc^(1/2))

More Similar Questions