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How do I solve 15^x-8+5=62 And round 3 places past the decimal?

Exponential and log equations

7 Answers

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  • 3 weeks ago

    15^(x - 8) + 5 = 62

    15^(x - 8) = 57

    Ln[15^(x - 8)] = Ln(57)

    (x - 8).Ln(15) = Ln(57)

    x - 8 = Ln(57)/Ln(15)

    x = 8 + [Ln(57)/Ln(15)]

    x = [8.Ln(15) + Ln(57)]/Ln(15)

    x ≈ 6.50702

    x = 6.507

  • 3 weeks ago

    15^x - 8 + 5 = 62

    15^x = 62 + 8 - 5

    15^x = 65

    x = (ln(65) + 2*i*pi*n) / ln(15), for any integer n

    x =~ 1.541 + 2.320in, for any integer n

    If x is a real number, then n = 0, so x = log[15](65) =~ 1.541

  • 3 weeks ago

    Looks at my answer to your other question which shows how to properly show what is in the exponent.

    I have a feeling you mean:

    15^(x - 8)  + 5 = 62

    But without the proper parenthesis, there is no way to know.

  • 3 weeks ago

    15^x-8+5=62

    15^x = 62+ 8 – 5 = 65

    log base 15 (15^x) = log base 15 (65)

    x = 1.541473

  • 3 weeks ago

    How about writing the question more clearly

    15^x - 8 + 5 is the same as 15^x - 3. why write both -8 and 5

    Or is it 15^(x-8)?

    15^(x-8) = 57

    log(57)/log(15) = 1.49

    15^(x-8) = 15^(1.49)

    x-8 = 1.49

    x = 9.49

  • ?
    Lv 7
    3 weeks ago

    15^x - 8 + 5 = 62

    15^x = 65

    x = log(65)/log(15)

    x ≈ 1.5415

  • ?
    Lv 7
    3 weeks ago

    15^x - 8 + 5 = 62

    15^x = 62+8-5 = 65

    xlog15 = log65

    x = log65/log15 = 1.541

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