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Zorluk: KolayIndices and Logarithms

If log10(x)+log10(5)=2\log_{10}(x) + \log_{10}(5) = 2, what is the value of xx?

  1. 20Cevap
  2. B
    95
  3. C
    10
  4. D
    40

Cevap

20
Using the logarithmic product identity logb(A)+logb(B)=logb(AB)\log_b(A) + \log_b(B) = \log_b(AB), the left side simplifies to log10(5x)=2\log_{10}(5x) = 2. Converting to exponential form gives 5x=102=1005x = 10^2 = 100, which simplifies directly to x=20x = 20.

Adım Adım Çözüm

1
Apply the product law of logarithms
log10(5x)=2\log_{10}(5x) = 2
The sum of logarithms with the same base equals the logarithm of their product: logb(A)+logb(B)=logb(AB)\log_b(A) + \log_b(B) = \log_b(AB).
2
Convert the logarithmic equation to exponential form
5x=102=1005x = 10^2 = 100
By definition of logarithms, if logb(y)=c\log_b(y) = c, then y=bcy = b^c.
3
Solve for xx
x=1005=20x = \frac{100}{5} = 20
Divide both sides of the linear equation by 55.

Anahtar Kavram

Logarithmic Product Law and Exponential Conversion
Tahmini Süre:45s
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