Amy asked in Science & MathematicsMathematics · 1 decade ago

How do you evaluate log 10 4+log 10 25?

7 Answers

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  • 1 decade ago
    Favorite Answer

    a property of logarithms states that

    logb ac = logb a + logb c

    therefore

    log10 4 + log10 25 = log10 (4*25)

    =log10 (100)

    =2

  • axtell
    Lv 4
    4 years ago

    Log 25 Log 4

  • 1 decade ago

    = log 10 (4 * 25)

    = log 10 100

    = 2

  • 1 decade ago

    Logs are exponents. When you add exponents you are multiplying. So finding the answer to "log4 + log25" means you are multiplying "4 x 25" Since we know that 4 x 25 = 100 - and, since you are dealing in Base 10 logs, the answer to "log4 + log25" should be 2 because Log 10 100 = 2.

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  • Anonymous
    1 decade ago

    Well, this is the same thing as:

    log[10](100), because the laws of logarithms state that if you have:

    log[b]a+log[b]c (b being the same base), you can multiply a and c together, to have:

    log[b](ac)

    Now, this is an easy logarithm to figure out.

    10 to the power of what equals 100? Well let's put this into an equation really quick:

    10^x=100

    We can easily see that x=2 therefore the answer is 2.

    Have a nice day now!! :-)

    Source(s): Grade 10 Math
  • 1 decade ago

    log10 4 + log10 25 = log10 4 × 25 = log10 100 = 2

  • 1 decade ago

    log10(4) + log10(25) = log10(4 * 25) = log10(100) = 2

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