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scott8148 answered: 6619 problems
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Square-cubic-other-roots/138603: i'm a freshman i college not real good with math..just wanted to know if i was on the right track..9v=15...i came up with 6/1..

1 solutions

Answer 101151 by scott8148(6628) About Me  on 2008-04-25 21:21:21 (Show Source):
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first one looks good

remember PEMDAS __ 59–33÷(13-4²)–8 __ 59–33÷(-3)–8 __ 59-(-11)-8 __ 70-8 __ 62


Equations/138487: From daughters [age 14] schoolbook with no ISBN.
x+1 over 3 = -x over 6
Thanks, you are great. I am learning lots from browsing here
1 solutions

Answer 101113 by scott8148(6628) About Me  on 2008-04-25 12:34:41 (Show Source):
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multiplying by 6 __ 2(x+1)=-x __ distributing __ 2x+2=-x

adding x-2 __ 3x=-2 __ dividing by 3 __ x=-2/3


Travel_Word_Problems/138405: This question is from textbook Prentice Hall Algebra 1
A bathtub can be filled in 20 minutes with both faucets running. If the cold water faucet runs twice as fast as the hot water, how long would it take the cold water faucet to fill the tub itself?
1 solutions

Answer 101090 by scott8148(6628) About Me  on 2008-04-24 21:01:23 (Show Source):
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the cold water fills 2/3 of the tub while the hot water fills 1/3

the cold water fills twice as much and together they fill the whole tub (3/3)

if the cold water fills 2/3 of the tub in 20 min, it would take 30 min to fill the whole tub


Rate-of-work-word-problems/138408: This question is from textbook Prentice Hall Algebra 1
Tim can trim 10 trees in 2/3 the time it takes Tom. They trim trees together for 1 hour 11 minutes. Then Tom continues alone until a total of 10 trees are trimmed (it took him 35 minutes 30 seconds). Working alone, how long would it take Tim to trim 10 trees?
1 solutions

Answer 101088 by scott8148(6628) About Me  on 2008-04-24 20:55:20 (Show Source):
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let x="Tim alone", so 1.5x="Tom alone" __ they each do some fraction of the job

71/x+106.5/(1.5x)=1 __ 71/x+71/x=1 __ 142/x=1 __ 142=x


Quadratic_Equations/138418: This question is from textbook Algebra 2
How do you solve the equation? Please help thanks
(x + 2)(x-4) = 0

1 solutions

Answer 101085 by scott8148(6628) About Me  on 2008-04-24 20:39:19 (Show Source):
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in order for the product to be zero; one or both of the factors must be zero

individually setting the factors equal to zero will give the possible values for x

x+2=0 __ x=-2
x-4=0 __ x=4

these are both solutions to the equation


Miscellaneous_Word_Problems/138419: Please please help! This is a natural logorithm ? I got half, but now I am stumped, and I need it for tomorrow!!! Here it is:
Suppose that the function P=11+44 ln x represents the percentage of inbound e-mail in the U.S. that is considered spam, where x is the number of years after 2002.
Carry all calculations to six decimals on each intermediate step when necessary.
a) Use this model to approximate the percentage of spam in the year 2006 to the nearest tenth of a percent.
Answer: Approximately 37.5%
Show your work in this space: P = 11 + 44ln 4
P = 11 + 44 × 0.602059
P = 11 + 26.490596
P = 37.490596
b) Use this model to determine in how many years it will take for the percent of spam to reach 85% provided that law enforcement regarding spammers does not change.
Answer:
Show your work in this space:
85=11+44 ln x
74=44 ln x (now am stuck)

1 solutions

Answer 101083 by scott8148(6628) About Me  on 2008-04-24 20:33:00 (Show Source):
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check your work for part a) __ it looks like you used log instead of ln


dividing by 44 __ 74/44=ln(x) __ taking antilog __ e^(74/44)=x


Equations/138428: i have a problem and i dont know what to do first the problem is ,
-7+6x = 7x-10
1 solutions

Answer 101082 by scott8148(6628) About Me  on 2008-04-24 20:18:19 (Show Source):
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adding 10 __ 3+6x=7x __ subtracting 6x __ 3=x

since these steps are addition/subrtaction, the order that they are done in makes no difference


Miscellaneous_Word_Problems/138316: Please help, I am lost at how to do this problem.
The combined area of a square and a rectangle is 64 centimeters. The width of the rectangle is 2 centimeters more than the lenght of a side of the square, and the lenght of the rectangle is 2 centimeters more than it width. Find the dimensions of the square and the rectangle?
1 solutions

Answer 101022 by scott8148(6628) About Me  on 2008-04-24 13:59:33 (Show Source):
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let x="side of square"

"The width of the rectangle is 2 centimeters more than the lenght of a side of the square"
__ x+2

"the lenght of the rectangle is 2 centimeters more than it width" __ x+2+2 __ x+4

64=(x)(x)+(x+2)(x+4) __ 64=x^2+x^2+6x+8 __ dividing by 2 __ 32=x^2+3x+4

subtracting 32 __ 0=x^2+3x-28 __ factoring __ 0=(x+7)(x-4)

x=-7 and x=4 __ negative value not realistic


Miscellaneous_Word_Problems/138321: Please help me if you can.
The area of a triangular sheet of paper is 28 square inches. One side of the triangle is 2 inches more than three times the lenght of the altitude to that side. Find the lenght of that side and the altitude to the side?
Thank you
1 solutions

Answer 101021 by scott8148(6628) About Me  on 2008-04-24 13:46:54 (Show Source):
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let x=altitude

"One side of the triangle is 2 inches more than three times the lenght of the altitude to that side"
__ 3x+2

area=1/2 times altitude times base __ 28=(1/2)(x)(3x+2)

dividing by 1/2 __ 56=3x^2+2x __ subtracting 56 __ 0=3x^2+2x-56

factoring __ 0=(3x+14)(x-4) __ x=-14/3 and x=4 __ negative value not realistic

altitude is 4 and side is 14


Quadratic_Equations/138242: Solve.
2x + 1 < 13
The solution is
1 solutions

Answer 100950 by scott8148(6628) About Me  on 2008-04-23 20:13:23 (Show Source):
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subtracting 1 __ 2x<12 __ dividing by 2 __ x<6


Quadratic_Equations/138251: Solve
0.7x + 1 <_ 1.5x -6 (the _ is supposed to be under the <)
The solution is xlx? ?
Can you help with this please?
1 solutions

Answer 100948 by scott8148(6628) About Me  on 2008-04-23 20:09:22 (Show Source):
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subtracting 0.7x __ 1<=0.8x-6 __ adding 6 __ 7<=0.8x __ dividing by 0.8 __ 8.75<=x or x>8.75


logarithm/138213: Looking to verify adding (or subtracting) logarithms to a single logarithm. I have: "log 5 250 - log 5 10". I believe that if they are the same base, you can simply substract the 250 from 10 to equal 240 (e.g. log 5 240). Right? Thanks in advance.
1 solutions

Answer 100947 by scott8148(6628) About Me  on 2008-04-23 20:04:15 (Show Source):
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no, not right

subtracting logs is dividing numbers (adding logs is multiplying numbers)

log5(250/10) __ log5(25) __ log5(5^2) __ 2, by definition


Polynomials-and-rational-expressions/138229: I can't figure this out!!!
I have to factor 2x^3+40x^2+200x
I have tried fro 30 mins. The 200 and the 3 (exponent confuse me)
1 solutions

Answer 100946 by scott8148(6628) About Me  on 2008-04-23 19:55:54 (Show Source):
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common factors first __ (2x)(x^2+20x+100) __ (2x)(x+10)(x+10)


Numbers_Word_Problems/138231: Please help!! I can't figure out this question.
Twice the difference of 7 times a number and 4 yields the same result as the same number increased by 6.
1 solutions

Answer 100943 by scott8148(6628) About Me  on 2008-04-23 19:52:06 (Show Source):
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let x=number

"Twice the difference of 7 times a number and 4" __ 2(7x-4)

"yields the same result as" __ =

"the same number increased by 6" __ x+6

14x-8=x+6 __ 13x=14


Radicals/138243: Could you help me to solve the equation:
16/x^2=8/x+6
I know the LCD is x^2(x+6) and I multiply each term and I get
16(x+6)=8x^2
which turns into the equation
8x^2-16x+96=0 (right?)
which is where I get confused. I'm not sure if I am suposed to factor it out or use the quadratic formula to solve it. I know though that the answer involves a square root.
Please help!
1 solutions

Answer 100940 by scott8148(6628) About Me  on 2008-04-23 19:40:27 (Show Source):
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the 96 should be negative __ dividing by 8 __ x^2-2x-12=0

not factorable, so use quadratic formula __ x=[2 +- sqrt(4+48)]/2 __ x=1 +- sqrt(13)


Quadratic_Equations/138029: Solve by the substitution method.
4x+4y=-4
-2x+y=11
What is the solution to the system?
Help with this too please?!?!!
1 solutions

Answer 100929 by scott8148(6628) About Me  on 2008-04-23 16:29:59 (Show Source):
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adding 2x to the 2nd equation __ y=11+2x

SUBSTITUTING into the 1st equation __ 4x+4(11+2x)=-4 __ 4x+44+8x=-4 __ 12x=-48 __ x=-4

SUBSTITUTING into the 2nd equation __ -2(-4)+y=11 __ 8+y=11 __ y=3


Quadratic_Equations/138033: Hockey teams receive 2 points if they win and 1 point for a tie. One season a team won a championship with 54 points. They won 9 more games than they tied. How many wins and how many ties did the team have?
Help me please I am terrible with these word/math problems.
1 solutions

Answer 100927 by scott8148(6628) About Me  on 2008-04-23 16:23:06 (Show Source):
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let x=ties, so x+9=wins __ 1(x)+2(x+9)=54 __ x+2x+18=54 __ 3x=36 __ x=12

12 ties and 21 wins


real-numbers/138209: Can you please help me find all the real solutions to this problem +11x=2x%5E2%2B12+
1 solutions

Answer 100926 by scott8148(6628) About Me  on 2008-04-23 16:17:28 (Show Source):
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subtracting 11x __ 0=2x^2-11x+12 __ factoring 0=(2x-3)(x-4)

so x=3/2 and x=4


Quadratic_Equations/138058: The perimeter of a rectangle is 144 inches. The length exceeds the width by 46 inches. Find the length and the width.
The length in inches ??
The width in inches ??
Help me please. I am so failing this clas s Ijust cant grasp this stuff. Help!!
1 solutions

Answer 100925 by scott8148(6628) About Me  on 2008-04-23 16:14:56 (Show Source):
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let x=width

"The length exceeds the width by 46 inches" __ so x+46=length

perimeter is twice the length plus twice the width __ 144=2(x+46)+2(x)

144=2x+92+2x __ 144=4x+92 __ 52=4x __ 13=x

width is 13 and length is 59


Quadratic_Equations/138085: This question is from textbook Prentice Hall Algebra 1
What should be the diameter (d) of a pizza so that it has the same areas as two 10-in.-diameter pizzas? Do you get more to eat with a 15-in. pizza or two 10-in. pizzas?
1 solutions

Answer 100919 by scott8148(6628) About Me  on 2008-04-23 15:40:25 (Show Source):
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pi(d/2)^2=2*pi*5^2 __ (d^2)/4=50 __ d^2=200 __ d=10*sqrt(2) __ approx 14.14

15 is more than 14.14 so the one pizza is more


test/138086: An existing garden is the shape of a rectangle with a length of 15 ft and a width of 9 ft. A border of shrubs is to be placed around the garden. The border will have the same width all the way around the garden. Enough shrubs are needed to fill the +256+ft%5E2+ area formed by the border. What is the width of the border?
1 solutions

Answer 100918 by scott8148(6628) About Me  on 2008-04-23 15:34:29 (Show Source):
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let x=width __ area=garden+border __ (9+2x)(15+2x)=9*15+256 __ 9*15+48x+4x^2=9*15+256

subtracting 9*15+256 __ 4x^2+48x-256=0 __ dividing by 4 __ x^2+12x-64=0

factoring __ (x+16)(x-4)=0 __ x=-16 and x=4 (-16 not realistic)


logarithm/138091: help..log base 5 2500-log base5 4 = ??? I have log base5 2500 over 4 which gives me log base5 625.. now what? do I do log 625/log 5 and get 2.795/.6989 which then equals 3.999?? Not sure if I'm doing this right.
1 solutions

Answer 100917 by scott8148(6628) About Me  on 2008-04-23 15:23:42 (Show Source):
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log5(625) __ log5(25*25) __ log5(5*5*5*5) __ log5(5^4)=4, by definition


test/138096: write a single logarithm....please explain how you got it-I've got to learn this
loga x + loga y - loga m
1 solutions

Answer 100916 by scott8148(6628) About Me  on 2008-04-23 15:19:56 (Show Source):
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adding logs is multiplying numbers __ subtracting logs is dividing numbers

loga(xy/m)


Polynomials-and-rational-expressions/138112: A rectangle is twice as long as it is wide and its area is 968sq ft. What is its lenghth?
1 solutions

Answer 100915 by scott8148(6628) About Me  on 2008-04-23 15:12:02 (Show Source):
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let x=length, so x/2=width __ area=(length)(width) __ 968=x(x/2) __ 1936=x^2 __ 44=x


Miscellaneous_Word_Problems/138113: A rectangle is twice as long as it is wide and its area is 968 square feet, what is its lenghth?
1 solutions

Answer 100914 by scott8148(6628) About Me  on 2008-04-23 15:10:14 (Show Source):
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let x=length, so x/2=width __ area=(length)(width) __ 968=x(x/2) __ 1936=x^2 __ 44=x


Miscellaneous_Word_Problems/138114: A driver gear with 75 teeth running at 32 rpm (revolutions per minute) will transfer what rpm to a driven gear with 24 teeth?
1 solutions

Answer 100912 by scott8148(6628) About Me  on 2008-04-23 15:02:54 (Show Source):
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the tooth ratio times the rpm __ (75/24)32=100


Money_Word_Problems/138088: Hi,
I have the answer to this problem, but I did not solve it algebraically. Can you help me with how it would be solved through algebra? Here is the problem:
If a bank compounds continuously, then the formula used is A=Pe^rt
where e is a constant and equals approximately 2.7183, P = $3000 and r=6%, how long will it take (t) to double the P? In other words, if A=6000, P=3000, e= 2.7183 and r=6%, solve for t

1 solutions

Answer 100867 by scott8148(6628) About Me  on 2008-04-22 22:10:06 (Show Source):
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dividing by P (3000) __ .5=e^(.06t)

taking natural log __ ln(.5)=.06t

dividing by .06 __ [ln(.5)]/.06=t


e is the base for natural logs


logarithm/138093: log base6 12+ log base6 18 = log base 6 (12)(18)= log base6 216.....now I'm stuck, would I do log 216/log 6 =2.334/.7781 = 2.999?????
1 solutions

Answer 100865 by scott8148(6628) About Me  on 2008-04-22 22:05:09 (Show Source):
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keep the calculator turned off

log6[(2)(6)(3)(6)] __ log6[(6)(6)(6)] __ log6(6^3) __ by definition, 3


Probability-and-statistics/138079: This question is from textbook Prentice Hall Algebra 1
I would very much appreciate if you could answer this question I do not know what category this is:
The speed of a boat in still water is 10km/h. The boat travels 12km upstream and 28km downstream in a total time of 4 hours. What is the speed of the stream?

Thank You
1 solutions

Answer 100861 by scott8148(6628) About Me  on 2008-04-22 21:58:46 (Show Source):
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let x=current __ rate upstream is 10-x and rate downstream is 10+x

d=rt, so t=d/r __ time up plus time down is 4 hr

4=[12/(10-x)]+[28/(10+x)] __ multiplying by (10-x)(10+x) __ 4(10-x)(10+x)=12(10+x)+28(10-x)

400-4x^2=400-16x __ adding 4x^2-400 __ 0=4x^2-16x __ dividing by 4 __ 0=x^2-4x

factoring __ 0=x(x-4) __ x=0 and x=4 (zero is not realistic)


Square-cubic-other-roots/137998: I'm 27 and not in school anymore. I didn't want you to think that I'm cheating on homework. I'm just trying to explain things better to my neice. I can't remember how to do complex cubes. This is the one I'm stuck on.
I need to find all three of the complex cube roots of 27 in the A+Bi form.
1 solutions

Answer 100849 by scott8148(6628) About Me  on 2008-04-22 19:39:51 (Show Source):
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x^3=27 __ x^3-27=0

factoring difference of cubes __ (x-3)(x^2+3x+9)=0

using quadratic formula __ x=(-3 +- sqrt[(3^2-(4)(1)(9)])/[(2)(1)] __ x=[-3 +- sqrt(-27)]/2
__ x=-3/2 +- [(3/2)sqrt(3)]i

one root is real (3) __ roots are 3+0i, (-3/2)+[(3/2)sqrt(3)]i, (-3/2)-[(3/2)sqrt(3)]i


Mixture_Word_Problems/137859: I need help understanding this, Please help. P Varies Directly as R and inversly as the square of S. If P = 175 and R = 252, and S = 6, Find P When R = 196 and S = 7
1 solutions

Answer 100772 by scott8148(6628) About Me  on 2008-04-21 20:15:23 (Show Source):
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you need to find the constant of variation (usually written as k)

P=kR/S^2 __ 175=k*252/36 __ 25=k

P=25*196/49 __ P=100