Tutors Answer Your Questions about Exponential-and-logarithmic-functions (FREE)
Question 605563: Ok so the question is, "Solve the following logarithmic equation."
the brackets [] = the base or b
log[5](x+3) = 4 - log[5](x+123)
log[5](x+3)(x+123) = 4
product rule above
exponential form below
5^4 = (x+3)(x+123)
625 = x^2 + 126x + 369
0 = x^2 + 126x - 256
I am stuck here and could use help getting the zeroes.
Click here to see answer by solver91311(24713)   |
Question 606063: I know this shouldn't be hard, we are doing a study sheet for a test and can't get past the second problem.
simplify each logarithm (a calculator should not be needed)
log base (1/3) 9 so this is 1/3^x equals 9
if I use the change of base formula I get -.5 or 1/2 but when I try to work 1/3^(1/2) I don't get 9
what am I doing wrong, and I can't use a calculator anyway so how do I do this without the change of base formula?
thank you
Click here to see answer by jim_thompson5910(35256) |
Question 606080: simplify
this one is hard to write but it looks like
4^log base4 x
i think you take the 4(the 4 that is in front) and put it above the x.
then it would be log base 4 x^4
do you put the 4 equal to the x or the way I did it above?
Thank you
Click here to see answer by stanbon(75887) |
Question 607161: Please help!I thought I had the correct answers, but I got them wrong.
find the intercepts and traces for the graph 7x + 3y-z = 42
x-intercept (I had 5,0,0) y-intercept ( I had 0,2,-1) z-intercept (I had 0,0,-1)
xy trace (I had 5,2,0) yz trace (I had (0,2,-1) xz trace (I had 5,0,1)
thank you so much!
Click here to see answer by jim_thompson5910(35256) |
Question 607380: The half-life of a certain radioactive material is 67 days. An initial amount of the material has a mass of 25 kg. Write an exponential function that models the decay of this material. Find how much radioactive material remains after 27 days. Round your answer to the nearest thousandth.
Click here to see answer by ewatrrr(24785)  |
Question 607736: Please help me solve this math problem: Graph the function.State the domain and range.
y=log3(x+1)
I have a scientific calculator and I forgot how to plug the numbers in when using log I would appreciate it if you can help me with that too thanks!
Click here to see answer by Alan3354(69443)  |
Question 607736: Please help me solve this math problem: Graph the function.State the domain and range.
y=log3(x+1)
I have a scientific calculator and I forgot how to plug the numbers in when using log I would appreciate it if you can help me with that too thanks!
Click here to see answer by jim_thompson5910(35256) |
Question 607998: The attenuation of a 900 MHz mobile phone signal by a concrete wall reinforced with steel mesh is described by,
I(t)=1.2e^(-0.138t)
where t is the thickness of the wall in cm, and I(t) is the intensity
of signal, in mW/m2, measured on the interior of the wall.
(a) What is the signal intensity incident on the exterior of the
wall?
(a) Answer - I think is t=0
900=1.2e^1.2^-0.138*0
900=1.2*1
900/1.2=1.2*1/1.2
750=1
750/1=0
750
(b) If the wall is 25 cm thick, what intensity will be measured
inside? Round your answer to 2 decimal places.
(b) Answer - I think is
750=1.2e^-0.138*0.25
750=1.2e^-0.0345
750/1.2*0.966088=1.2*0.966088/1.2*0.966088
646.9389952
Approx =647
(c) What thickness of wall will drop the intensity to half of the
exterior value? Round your answer to 2 decimal places.
(c) Not sure a bit lost
Click here to see answer by scott8148(6628)  |
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