Math

posted by .

How do I solve e^(2x)+10e^(x)-75=0 and 3^(x+2)=7^(x-5)?

  • Pre Calc -

    For e^(2x)+10e^(x)-75=0
    Let
    y=e^x
    then
    y² = e^(2x)
    Substitute in above equation,
    y²+10y-75=0
    Factor and solve for y.
    Note that the domain of y (=e^x) is (0,∞), so any negative root for the quadratic equation must be rejected.

    For 3^(x+2)=7^(x-5)
    take logarithm on both sides, and apply the exponent rule to get
    (x+2)*ln 3 = (x-5)*ln 7
    Solve for x. I get x=14 approx.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Math

    How do I solve 3log10of(x-6)=11 and e^(2x)+10e^(x)-25=0?
  2. Astronomy

    The hottest stars have surface temperatures of about 40,000 K. At what wavelength do they emit the most radiation?
  3. Chemisdtry - Lewis Structures (check + help)

    Draw Lewis structures for each of the following ion: CO3 (2-) I tried this method below, i do not know where am i going wrong, please help me understand this concept for ions. Valence Electrons 4e- + 18e- = 22e- Noble gas Config 8e- …
  4. Math(Please, please help)

    1/[N2O] = 1/(1.75M) + (1.10E-3M^-1 S^-1)(1852s) [N2O] = 0.383 M I know I posted a similar question but I am having trouble with this one as well. Should I do 1/1.75 first and then add 1.10e-3 and then multiply by 1852?
  5. Math(Thank you for your help)

    1/[N2O] = 1/(1.75M) + (1.10E-3M^-1 S^-1)(1852s) [N2O] = 0.383 M I know I posted a similar question but I am having trouble with this one as well. Should I do 1/1.75 first and then add 1.10e-3 and then multiply by 1852?
  6. Chemistry

    1/[N2O] = 1/(1.75M) + (1.10E-3M^-1 S^-1)(1852s) [N2O] = 0.383 M I know I posted a similar question but I am having trouble with this one as well. Should I do 1/1.75 first and then add 1.10e-3 and then multiply by 1852?
  7. Math(Please respond)

    .50 - x / x = 3.20e-1 I need to solve for x. I was going to do .50 X 3.20e-1 and then take the square root but this is not correct. I am not sure what to do. Thank you for your help. Math(Please help) - Reiny, Tuesday, April 17, 2012 …
  8. Chemistry(Please check)

    .50 - x / x = 3.20e-1 I need to solve for x. I was going to do .50 X 3.20e-1 and then take the square root but this is not correct. I am not sure what to do. Thank you for your help. Math(Please help) - Reiny, Tuesday, April 17, 2012 …
  9. Chemistry

    .50 - x / x = 3.20e-1 I need to solve for x. I was going to do .50 X 3.20e-1 and then take the square root but this is not correct. I am not sure what to do. Thank you for your help. Math(Please help) - Reiny, Tuesday, April 17, 2012 …
  10. Math

    Solve for t using natural logarithms. 7e^3t = 10e^2t

More Similar Questions