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? asked in Science & MathematicsMathematics · 8 years ago

Solve the following exponential equation.?

e^(3x+10) = 39^(4x+6)

Write answer as both an exact expression and decimal approximation. (Rounded to 2 decimal places)

Use e=2.71828182845905

3 Answers

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  • Melvyn
    Lv 7
    8 years ago
    Favorite Answer

    3x+10 = (4x+6) ln 39

    = 4x ln 39 + 6 ln 39

    x(4 ln 39 -3)=10-6 ln 39

    x= (10 - 6 ln 39)/(4 ln 39 - 3)

    = -1.03

  • Luke
    Lv 6
    8 years ago

    e^(3x+10) = 39^(4x+6)

    take the natural log of both sides

    ln(e^(3x+10)) = ln(39^(4x+6))

    (3x+10) = ln(39^(4x+6))

    by the exponent/factor property of logarithms

    (3x+10) = (4x+6)ln(39)

    3x+10 = 4xln(39)+6ln(39)

    3x - 4xln(39) = 6ln(39) - 10

    x(3 - 4ln(39)) = 6ln(39) - 10

    the exact answer is

    x = (6ln(39) - 10) / (3 - 4ln(39))

    the approximate answer is

    -1.028069021

    this can be verified using an MS Excel worksheet formula

    =(6*LOG(39,EXP(1))-10)/(3-4*LOG(39,EXP(1)))

  • ?
    Lv 7
    8 years ago

    3x+10 = ln [ 39^(4x+6)] = (4x+6)ln39

    x(3-4ln39) = [6ln39-10]

    x = [6ln39-10]/(3-4ln39)

    x = -1.02807

    Rounds to

    x = -1.03

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