Questions on Algebra: Logarithm answered by real tutors!

Tutors Answer Your Questions about logarithm (FREE)

Question 208108: Hello! I was trying to find hydrogen ion concentration with a ph of 12.4.
with three place values.
12.4= -log[H+]
I was trying to figure out where to go from here.
Click here to see answer by Alan3354(30993)

Question 208100: Good afternoon! I am trying to solve this problem.
4000=2,000*e^(0.08)*t
4,000/2,000=e^0.08t
2=e^0.05t
ln2=0.08*t
I got this far and got stuck.
Click here to see answer by ankor@dixie-net.com(15649)

Question 206833: How long would it take for $1000 to grow to $4300 at 5% interest. Compounded Continously. Please go step by step. Thanks.
Click here to see answer by Alan3354(30993)

Question 208147: the number of homes built can be modeled by an exponential function,
H= p * at , where p is the number of new homes built in the first year recorded.
p=10 t =3 a=2
I'm not sure how to calculate
Click here to see answer by rfer(12657)

Question 208183: the number of homes built can be modeled by an exponential function,
H= p * at , where p is the number of new homes built in the first year recorded.
p=10 t =3 a=2
I'm not sure how to calculate : the number of homes built can be modeled by an exponential function,
H= p * a^t , where p is the number of new homes built in the first year recorded.
p=10 t =3 a=2
I'm not sure how to calculate

Click here to see answer by rapaljer(4667)

Question 208181: the number of homes built can be modeled by an exponential function,
H= p * a(t) , where p is the number of new homes built in the first year recorded.
p=10 t =3 a=2
im not sure how to caculate it.
Click here to see answer by rapaljer(4667)

Question 208633: solve for x. log(base x)16 = 4
Click here to see answer by nerdybill(6958)

Question 208905: Solve the equation for x.
e^(ax) = Ce^(bx), where a is not equal to b
Click here to see answer by nerdybill(6958)

Question 208979: i need help to simplify fully this logarithm expression, please...

thank you!!!
Click here to see answer by Theo(3458)

Question 209155: can someone please help.
solve each equation for x
1. 4^(x + 1) = 4^(3x - 5)
2.8^2x = 8^(3x - 1)
3.10^6x = 100^(x + 6)

use your calculator to solve for x.round to the nearest thousandth
1.10^2.3 = x
2.e^x = 9
3.10^x = 15
4.e^ -1.5 = x
thanks for the help.I really appreciate it.
Click here to see answer by stanbon(57307)

Question 209446: instead of using table what is the constant or formula to find log of any number with base 10.eg:log13(base10); log12(base 10)
Click here to see answer by rfer(12657)

Question 209446: instead of using table what is the constant or formula to find log of any number with base 10.eg:log13(base10); log12(base 10)
Click here to see answer by Alan3354(30993)

Question 209511: Please help me understand how to do this...
Rewrite as a logarithmic equation.
2^(-4)=1/16?
Click here to see answer by Alan3354(30993)

Question 209694: I had 10 problems on this.
i was able to complete all except 2.
e^2x - 3e^x + 2 = 0
i believe i am supposed to move the 2 to the other side.
but im not quite sure how to solve this problem
id greatly appreciate ur help
Click here to see answer by nerdybill(6958)

Question 209697: ok.
i have this problem
ln(x-2) + ln(2x-3) = 2lnx
please help me
i have no understanding of this problem
Click here to see answer by nerdybill(6958)

Question 209715: i have the problem:
ln(x+1)^2=2
i worked it out as:
ln(x+1)^2=2
(x+1)^2=e^2
2(x+1)=7.38906
2x+2=7.38906
2x\2 = 5.38906
x=2.69453
i know i did something wrong becausemy answer is not working out.
help me plz!
Click here to see answer by Alan3354(30993)

Question 209720: i have the problem:
ln(x+1)^2=2
i worked it out as:
ln(x+1)^2=2
(x+1)^2=e^2
2(x+1)=7.38906
2x+2=7.38906
2x\2 = 5.38906
x=2.69453

i know i did something wrong becausemy answer is not working out.
help me plz!
what did i do wrong?
thanks in advanced
Click here to see answer by stanbon(57307)

Question 209708: I need major help on logarithms.
if i have:
ln(x-2)+ ln(2x-3)= 2lnx
i know that im supposed to
have
ln((x-2)(2x-3))=lnx^2
which would eliminate the ln
but what do i do afterwards?
Click here to see answer by Alan3354(30993)

Question 209750: i worked this problem like this:
(e^2x) - (3e^x) + 2 = 0
(e^2x) - (3e^x) = -2
e^(2x\x^3) = e^(-2)
(2\x^2)= e^(-2)
2= e^(-2x^2)
(2\e^-2) = x^2
sqrt(14.778)= sqrt(x^2)
x=3.844
i tried my answer. but it doesnt work out.
Click here to see answer by stanbon(57307)

Question 209731: i worked this problem like this:
e^2x - 3e^x + 2 = 0
e^2x - 3e^x = -2
e^(2x\x^3) = e^(-2)
(2\x^2)= e^(-2)
2= e^(-2x^2)
(2\e^-2) = x^2
sqrt(14.778)= sqrt(x^2)
x=3.844
i tried my answer. but it doesnt work out.
what did i do wrong?
thanks in advance

Click here to see answer by jsmallt9(3296)

Question 210129: find the value of the expressions using logarithms. 1215^(3/2)
Click here to see answer by checkley77(12569)

Question 210216: Express as a single logarithm.
log7 4 - log7 12
A)log^14 1/3
B)log^7 1/3
C)log^14 3
D)log^7 3
Click here to see answer by user_dude2008(1861)

Question 210641: LOG2X=-1
Click here to see answer by tutor_paul(490)

Question 210767: I need help with the problem The question says to solve for the missing variable. SO what i did was made both sides in terms of e and then set the exponents equal to each other and i get 8/11 which i am told is not correct. help please?
Click here to see answer by stanbon(57307)

Question 210783: It has been a while since i have done logarithms so how would you go about doing this problem?
4x3^x = 7x5^x
I know that you want to solve for x but I am not sure how.
Thanks
Click here to see answer by jim_thompson5910(28593)

Question 210892: please help me solve log(2x-1)-log(x+6)=log5
Click here to see answer by nerdybill(6958)

Question 210995: 10^4 = 10,000
Rewrite as an equivalent logarithmic equation. Do not solve.

Click here to see answer by Alan3354(30993)

Question 211013: Express the given quantity as a single logarithm. ln(a + b) + ln(a - b) - 8 ln(c)
Click here to see answer by ankor@dixie-net.com(15649)

Question 210996: Log7 100
Find each of the following logarithms using the change of base formula. Round answers to the nearest ten thousandth.

Click here to see answer by Earlsdon(6287)

Question 211020: Find the pH of an acidic substance of your choice. Using this pH, show how to find the hydrogen ion concentration, [H+], of the substance using the formula. Discuss the meaning of pH and [H+], the pH scale and why your chosen substance is acidic. Use scientific notation or enough decimal places so that your answer has at least 3 place values. For example, either use 3.44*10-6 or 0.00000344.
I picked Baking soda. Baking soda is NaHCO3.
The formula is:
pH = -log10 [H+]
Baking soda has a pH of 9. It is a base, since the pH is above 7.
You first plug 9 into the formula:
9 = -log10 [H+]
Then divide by -1:
-9 = log10 [H+]
Take 10 on each side:
10^-9 = 10log10 [H+]
Simplify:
10^-9 = [H+]
[H+] = 10^-9 mol/L

Click here to see answer by stanbon(57307)

Question 211035: Using the Library, web resources, and/or other materials, find a real-life application of a quadratic function. State the application, give the equation of the quadratic function, and state what the x and y in the application represent. Choose at least two values of x to input into your function and find the corresponding y for each. State, in words, what each x and y means in terms of your real-life application. Please see the following example. Do not use any version of this example in your own post. You may use other variables besides x and y, such as t and S depicted in the following example, but you may not use that example. Be sure to reference all sources using APA style.
Typing hint: To type x-squared, use x^2. Do not use special graphs or symbols because they will not appear when pasted to the Discussion Board.
When thrown into the air from the top of a 50 ft building, a ball’s height, S, at time t can be found by S(t) = -16t^2 + 32t + 50. When t = 1, s = -16(1)^2 + 32(1) + 50 = 66. This implies that after 1 second, the height of the ball is 66 feet. When t = 2, s = -16(2)^2 + 32(2) + 50 = 50. This implies that after 2 seconds, the height of the ball is 50 feet.
I used this. I wanted to know if I was correct.
Real life quadratic function application:
The formula s=-16t^2+vOt+sO
sO=initial height
vO=velocity in feet per second
t=time
The initial height of the mountain where you are standing is 300 feet.
I launch a rock in the air at 52 feet per second.
I want to find out how high it will be after 3 seconds.
Now let’s do the formula.
s=-16t^2+vOt+sO
=-16(3) ^2+52(3) +300
=-16(9) +156+300
=-144+465
s=312
So at 3 seconds, it's 312
This accurately describes the rock's height at any given time from the time of launch to the time.

Click here to see answer by stanbon(57307)

Question 211040: Express as an equivalent expression using the individual logarithms or x,y,and z:
log(sub a) x^4y^2z^3
Click here to see answer by stanbon(57307)

Question 211044: express as an equivalent expression that is a product: log(b)t^5
Click here to see answer by stanbon(57307)

Question 211044: express as an equivalent expression that is a product: log(b)t^5
Click here to see answer by Alan3354(30993)

Question 211042: graph: x=(1/4)^y
Click here to see answer by stanbon(57307)

Question 211288: log8 (3x+7) = log8 (7x+4) do you cancel the logs out to solve this problem? or how do you solve this problem?
Click here to see answer by jim_thompson5910(28593)

Question 211288: log8 (3x+7) = log8 (7x+4) do you cancel the logs out to solve this problem? or how do you solve this problem?
Click here to see answer by Alan3354(30993)

Question 211300: logx (1/8) = -3
how do you answer this?
Click here to see answer by jim_thompson5910(28593)

Question 211315: log4 (x^2 + 6) = log4 5x
how do i solve this???
Click here to see answer by jim_thompson5910(28593)

Question 211318: log2 (1/16)
how do you solve this??
Click here to see answer by stanbon(57307)

Question 211318: log2 (1/16)
how do you solve this??
Click here to see answer by ankor@dixie-net.com(15649)

Question 211317: logx 16 = -4
Click here to see answer by stanbon(57307)

Question 211321: how do you solve...
log(1/3) 27
Click here to see answer by Alan3354(30993)

Question 211372: Could someone please tell me if I did this right.
Evaluate the logarithmic equation for three values of x that are greater than 1, three values between 0 and 1, x to =0.
y=log3.5^x
x=2 so y=0.55
x=3 so y=0.88
x=4 so y=1.11
x=0.2 so y= - 1.28
x=0.5 so y= - 0.55
x=0.7 so y= - 0.28
x=1 so y=0
Click here to see answer by RAY100(1637)

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