See tutors' answers!

Algebra ->  Tutoring on algebra.com -> See tutors' answers!      Log On


   
By Tutor
 | By Problem Number | 

Tutor:
New! Get regular updates about newly solved problems via algebra.com's RSS system.

Recent problems solved by 'scott8148'

scott8148 answered: 6619 problems
Jump to solutions: 0..29 , 30..59 , 60..89 , 90..119 , 120..149 , 150..179 , 180..209 , 210..239 , 240..269 , 270..299 , 300..329 , 330..359 , 360..389 , 390..419 , 420..449 , 450..479 , 480..509 , 510..539 , 540..569 , 570..599 , 600..629 , 630..659 , 660..689 , 690..719 , 720..749 , 750..779 , 780..809 , 810..839 , 840..869 , 870..899 , 900..929 , 930..959 , 960..989 , 990..1019 , 1020..1049 , 1050..1079 , 1080..1109 , 1110..1139 , 1140..1169 , 1170..1199 , 1200..1229 , 1230..1259 , 1260..1289 , 1290..1319 , 1320..1349 , 1350..1379 , 1380..1409 , 1410..1439 , 1440..1469 , 1470..1499 , 1500..1529 , 1530..1559 , 1560..1589 , 1590..1619 , 1620..1649 , 1650..1679 , 1680..1709 , 1710..1739 , 1740..1769 , 1770..1799 , 1800..1829 , 1830..1859 , 1860..1889 , 1890..1919 , 1920..1949 , 1950..1979 , 1980..2009 , 2010..2039 , 2040..2069 , 2070..2099 , 2100..2129 , 2130..2159 , 2160..2189 , 2190..2219 , 2220..2249 , 2250..2279 , 2280..2309 , 2310..2339 , 2340..2369 , 2370..2399 , 2400..2429 , 2430..2459 , 2460..2489 , 2490..2519 , 2520..2549 , 2550..2579 , 2580..2609 , 2610..2639 , 2640..2669 , 2670..2699 , 2700..2729 , 2730..2759 , 2760..2789 , 2790..2819 , 2820..2849 , 2850..2879 , 2880..2909 , 2910..2939 , 2940..2969 , 2970..2999 , 3000..3029 , 3030..3059 , 3060..3089 , 3090..3119 , 3120..3149 , 3150..3179 , 3180..3209 , 3210..3239 , 3240..3269 , 3270..3299 , 3300..3329 , 3330..3359 , 3360..3389 , 3390..3419 , 3420..3449 , 3450..3479 , 3480..3509 , 3510..3539 , 3540..3569 , 3570..3599 , 3600..3629 , 3630..3659 , 3660..3689 , 3690..3719 , 3720..3749 , 3750..3779 , 3780..3809 , 3810..3839 , 3840..3869 , 3870..3899 , 3900..3929 , 3930..3959 , 3960..3989 , 3990..4019 , 4020..4049 , 4050..4079 , 4080..4109 , 4110..4139 , 4140..4169 , 4170..4199 , 4200..4229 , 4230..4259 , 4260..4289 , 4290..4319 , 4320..4349 , 4350..4379 , 4380..4409 , 4410..4439 , 4440..4469 , 4470..4499 , 4500..4529 , 4530..4559 , 4560..4589 , 4590..4619 , 4620..4649 , 4650..4679 , 4680..4709 , 4710..4739 , 4740..4769 , 4770..4799 , 4800..4829 , 4830..4859 , 4860..4889 , 4890..4919 , 4920..4949 , 4950..4979 , 4980..5009 , 5010..5039 , 5040..5069 , 5070..5099 , 5100..5129 , 5130..5159 , 5160..5189 , 5190..5219 , 5220..5249 , 5250..5279 , 5280..5309 , 5310..5339 , 5340..5369 , 5370..5399 , 5400..5429 , 5430..5459 , 5460..5489 , 5490..5519 , 5520..5549 , 5550..5579 , 5580..5609 , 5610..5639 , 5640..5669 , 5670..5699 , 5700..5729 , 5730..5759 , 5760..5789 , 5790..5819 , 5820..5849 , 5850..5879 , 5880..5909 , 5910..5939 , 5940..5969 , 5970..5999 , 6000..6029 , 6030..6059 , 6060..6089 , 6090..6119 , 6120..6149 , 6150..6179 , 6180..6209 , 6210..6239 , 6240..6269 , 6270..6299 , 6300..6329 , 6330..6359 , 6360..6389 , 6390..6419 , 6420..6449 , 6450..6479 , 6480..6509 , 6510..6539 , 6540..6569 , 6570..6599 , 6600..6629, >>Next

Graphs/159032: can you please help me solve this -38%3E9x-+2

1 solutions

Answer 117142 by scott8148(6628) About Me  on 2008-09-25 23:39:55 (Show Source):
You can put this solution on YOUR website!
adding 2 __ -36>9x __ dividing by 9 __ -4>x


Graphs/159033: can you please help me solve this -38%3E9x-+2

1 solutions

Answer 117141 by scott8148(6628) About Me  on 2008-09-25 23:39:26 (Show Source):
You can put this solution on YOUR website!
adding 2 __ -36>9x __ dividing by 9 __ -4>x


Equations/159059: The center of a circular sunflower with a diameter of 4 centimeters is (-2,1). Write the equation that represents the sunflower.
Please help & Thanks!
1 solutions

Answer 117139 by scott8148(6628) About Me  on 2008-09-25 23:36:19 (Show Source):
You can put this solution on YOUR website!
(x-(-2))^2+(y-1)^2=(4/2)^2 __ x^2+4x+4+y^2-2y+1=4 __ x^2+y^2+4x-2y+1=0


Equations/159054: Write the equation of the line that passes through the point (2,-4) and is perpendicular to the line whose equation is y= -1/2x + 3
Please HELP!!
1 solutions

Answer 117138 by scott8148(6628) About Me  on 2008-09-25 23:31:05 (Show Source):
You can put this solution on YOUR website!
perpendicular lines have slopes that are negative reciprocals of each other

so, the slope of the new line is -1/(-1/2) or 2

using point-slope __ y-(-4)=2(x-2) __ y+4=2x-4 __ y=2x-8


Miscellaneous_Word_Problems/159043: For some reason I think I was once able to do this problem, but I forgot. Here's how it goes:
Two poles 20 feet and 80 feet high are 100 feet apart. What is the height of the point of intersection of the lines which run form the top of each pole to the foot of the other pole?
Quick help would be much appreciated.
Thanks, Cameron
1 solutions

Answer 117137 by scott8148(6628) About Me  on 2008-09-25 23:25:36 (Show Source):
You can put this solution on YOUR website!
the easiest solution is semi-graphical

picture the 80 foot pole standing on the origin and going up the y-axis

the 20 foot pole is standing on the x-axis, 100 feet from the origin

y=mx+b

the equation of the line from the top of 80 to the bottom of 20 is y=-.8x+80

the equation of the line from the bottom of 80 to the top of 20 is y=.2x

substituting __ .2x=-.8x+80 __ adding .8x __ x=80

substituting __ y=.2(80) __ y=16


Expressions-with-variables/159049: Please help me solve this problem. My math book has the answer in it but I don't understand how to get that answer. y=cx%2Bdx I'm suppose to solve for x. If you divide both sides by c+d you'll end up with y/c+d=2x. The right answer according to the book is y/c+d=x. If that is all you're suppose to do why is there only one x when there is clearly 2 on the right side? I appreciate your help. Thank you
1 solutions

Answer 117136 by scott8148(6628) About Me  on 2008-09-25 23:12:40 (Show Source):
You can put this solution on YOUR website!
the factors of cx+dx are x and c+d

using the distributive rule __ x*(c+d)=cx+dx

so y=x(c+d) __ dividing by (c+d) __ y/(c+d)=x


Equations/158900: Find the expression for the term for the sequences.
144,121,100,81,64,49
tn= ???????
Can you please help with what this equation is supposta be?I want to know how to do this, please help me step by step on how to make the equation?
thanks in advance,

1 solutions

Answer 117038 by scott8148(6628) About Me  on 2008-09-25 14:21:11 (Show Source):
You can put this solution on YOUR website!
the numbers are squares __ 12^2, 11^2, 10^2, 9^2, 8^2, 7^2

13-1=12 __ 13-2=11 __ 13-3=10 __ etc.

tn=(13-n)^2


Exponents-negative-and-fractional/158892: sir i have a problem on solving this equation.
i am trying to solve x and to simplify it.
question: logx 8=-3?
i convert it to exponential form x^-3=8
this are the formulas I've tried to solve it but I'm not sure if it is correct.
a). (x^-3)^3=(8)^3
x=8^3
x=512:answer
b). i change the negative exponent to positive and transpose it to 8
x=8^3
x=512:answer
c). i get the reciprocal of the exponent and change it to 1/3
it became x^1/3=8
then i do: (cube root of x)^3 = (8)^3
i cancel out cube root of x and it became
x=8^3
x=512:answer
please help me to figure out the answer of this problem because I'm about to go crazy.
for my last question..
is this formula i have given is correct??
i mean is there any possible way to solve it??,,
thank you sir in advance..
1 solutions

Answer 117032 by scott8148(6628) About Me  on 2008-09-25 13:42:25 (Show Source):
You can put this solution on YOUR website!
there is an error in a) __ (x^-3)^3=x^-9 __ the exponents multiply

try (x^-3)^(-1/3)=8^(-1/3) __ x=8^(-1/3) __ x=1/2



Polynomials-and-rational-expressions/158893: Factoring problem:
How do I factor this expression completely?
4x^2y - 8xy
thanks for your help.
1 solutions

Answer 117027 by scott8148(6628) About Me  on 2008-09-25 13:32:30 (Show Source):
You can put this solution on YOUR website!
take out common factors __ 4xy(x-2)


Polynomials-and-rational-expressions/158894: Factoring problem!
How do I factor this expression completely???
2x^2 - 22x + 60
Thanks, your help is extremely important.
1 solutions

Answer 117025 by scott8148(6628) About Me  on 2008-09-25 13:30:20 (Show Source):
You can put this solution on YOUR website!
common factors first __ 2(x^2-11x+30)

then, factors of 30 that sum to -11 __ 2(x-6)(x-5)


Complex_Numbers/158895: how to i make 273,000 into scientific notation
1 solutions

Answer 117024 by scott8148(6628) About Me  on 2008-09-25 13:27:33 (Show Source):
You can put this solution on YOUR website!
one non-zero digit to the left of the decimal point with the power of ten needed to equal the number

2.73x10^5


Polynomials-and-rational-expressions/158845: Ok, sorry but this word problem is killing me. It's not like any of the others I've done... Here it is:
"It is shown in engineering that the maximum load a cylindrical column of circular cross-section can hold varies directly as the fourth power of the diameter and inversely as the square of the height. If a column 16 feet high and 4 feet in diameter will support a load of 10 tons, how great a load will be supported by a column 20 feet high and 6 feet in diameter?"
Thanks!
Josh
1 solutions

Answer 116982 by scott8148(6628) About Me  on 2008-09-24 23:39:25 (Show Source):
You can put this solution on YOUR website!
L=kd^4/h^2 __ 10=k*4^4/16^2 __ 10=k

L=10*6^4/20^2 __ L=32.4


Matrices-and-determiminant/158789: This question is from textbook algebra 2
hello, thanks for helping me.....i'm on chapter 4.2 and i can't figure out how to multiply the matrices. I need to know the order in which i can multiply each row and column.
[5 3] [4 2 -1]
[0 1] [0 1 3]
1 solutions

Answer 116950 by scott8148(6628) About Me  on 2008-09-24 19:03:47 (Show Source):
You can put this solution on YOUR website!
multiplication is row times column
__ the rows of the 1st matrix must have the same number of elements as the columns of the 2nd matrix

multiply the pairs of elements and add the products to find the element in the product matrix
__ row m multiplied by column n will give element m,n in the product matrix

1,1 __ 5*4+3*0 __ 20
1,2 __ 5*2+3*1 __ 13
1,3 __ 5*(-1)+3*3 __ 4
2,1 __ 0*4+1*0 __ 0
2,2 __ 0*2+1*1 __ 1
2,3 __ 0*(-1)+1*3 __ 3

[20 13 4]
[0 1 3]


Problems-with-consecutive-odd-even-integers/158779: I need help figuring out how to write out this problem. The question reads: The larger of two consecutive even integers is 6 less than 3 times the smaller. Find the integers. This is a question on my daughter's homework. It isn't from the textbook as far as I know. I appreciate any help you can provide.
1 solutions

Answer 116946 by scott8148(6628) About Me  on 2008-09-24 18:49:14 (Show Source):
You can put this solution on YOUR website!
let n="1st integer", so n+2="2nd integer"

"The larger of two consecutive even integers" __ n+2

"is" __ =

"6 less than 3 times the smaller" __ 3n-6

n+2=3n-6 __ subtracting n and adding 6 __ 8=2n __ dividing by 2 __ 4=n

substituting __ 6=n+2


Percentage-and-ratio-word-problems/158783: A new fax machine was purchased for an office in HopeDale for $464.40 including tax. If the tax rate is 8 % , find the price of the fax machine before taxes.
I thought that I knew how to do this but my tutor says I am incorrect. Please help by telling me where I went wrong. Thanks !
8 % of 464.40 = 37.12
464.40 - 37.12 = 427.28
1 solutions

Answer 116940 by scott8148(6628) About Me  on 2008-09-24 18:41:05 (Show Source):
You can put this solution on YOUR website!
the $464.40 includes the tax __ if x is the price before tax, then 464.40 is 100% of x plus 8% of x

1.08x=464.40 __ dividing by 1.08 __ x=430


Geometric_formulas/158756: I know the formulas for finding the surface area of a sphere and the volume of a sphere. I need to use these formulas to find out the algebraic formula for the ratio of a sphere's surface area to its volume AND show logical steps on how I got it.
1 solutions

Answer 116926 by scott8148(6628) About Me  on 2008-09-24 16:11:35 (Show Source):
You can put this solution on YOUR website!
%28surface+area%29%2F%28volume%29=%284%2Api%2Ar%5E2%29%2F%28%284%2F3%29%2Api%2Ar%5E3%29 __ "cancelling" __ 1%2F%28%281%2F3%29r%29

multiplying by 3/3 (one) __ 3%2Fr


Inverses/158752: I am a parent who has been out of school for more than 20 years. I am trying to help my daugher understand a problem that is on her homework. The ditto is about Inverse Operations... and says to show two different ways to solve the equation. The equation is as follows:
5x - 1 = 2x + 8
Please Help!!!!!!!!!!!!
1 solutions

Answer 116925 by scott8148(6628) About Me  on 2008-09-24 15:58:38 (Show Source):
You can put this solution on YOUR website!
1 is subtracted on the left side, so the inverse operation is adding 1
__ 5x=2x+9

2x is added on the right side, so the inverse operation is subtracting 2x
__ 3x=9

3 is multiplied on the left side, so the inverse operation is dividing by 3
__ x=3



8 is added on the right side, so the inverse operation is subtracting 8
__ 5x-9=2x

5x is added on the left side, so the inverse operation is subtracting 5x
__ -9=-3x

-3 is multiplied on the right side, so the inverse operation is dividing by -3
__ 3=x


Coordinate-system/158735: Find the distance to the nearest hundredths between the given points. Then find the coordinates of the midpoint of the line segment connecting the points.
P1(6,-1)and P2(-3,-2)

I belive I have the first answer, 9. If this is correct, how do I find the midpoint?
1 solutions

Answer 116901 by scott8148(6628) About Me  on 2008-09-24 12:49:01 (Show Source):
You can put this solution on YOUR website!
9 is not correct

you need to use the Pythagorean theorem (distance formula)

finding the midpoint is fairly easy
__ just find the average of the 2 x-coordinates and the average of the 2 y-coordinates


Numbers_Word_Problems/158679: Its about Divisibility. Use this hints to figure out how many dancers there were. There are 40 5th graders in the school, but they did not all dance.When the dancers rehearsed in rows of 2, one dancer was left to dance alone. When the dancers rehearsed in rows of 3, two dancers were left to dance together. When the dancers rehearsed in rows of 4, three dancers were left to dance together. When the dancers rehearsed in rows of 5, finally every dancers was in a row! How many dancers could have been in the dance scene? Explain how you got your answer.
1 solutions

Answer 116899 by scott8148(6628) About Me  on 2008-09-24 11:22:34 (Show Source):
You can put this solution on YOUR website!
let N=number of dancers

"There are 40 5th graders in the school, but they did not all dance" __ N<40

"When the dancers rehearsed in rows of 2, one dancer was left to dance alone"
__ N is odd

"When the dancers rehearsed in rows of 5, finally every dancers was in a row!"
__ N is divisible by 5 __ 5, 15, 25, or 35

"When the dancers rehearsed in rows of 3, two dancers were left to dance together"
__ when N is divided by 3, the remainder is 2 __ 5 or 35

"When the dancers rehearsed in rows of 4, three dancers were left to dance together"
__ when N is divided by 4, the remainder is 3

N must equal 35


Exponents-negative-and-fractional/158693: how do i solve this? (-8000)^4/3.This is what i had tried but am now stuck. (#=square root) sorry i dont know the proper abv for it. 3^#8000^4 i know the answer is 160 000 but i dont understand how they got to that answer i tryed everything i can think of. i assume that bc i changed it to that format the negative just goes away. your help will be greatly apreciated (sorry about the spelling doing an all nighter.
1 solutions

Answer 116895 by scott8148(6628) About Me  on 2008-09-24 11:03:50 (Show Source):
You can put this solution on YOUR website!
when you have a fractional exponent, the numerator is a power and the denominator is a root

8000^(4/3)=[cuberoot(8000)]^4

cuberoot(8000)=[cuberoot(8)]=2*10=20

20^4=(2^4)*(10^4)=16*10000=160000


Money_Word_Problems/158703: This question is from textbook
i'm looking for what my variable is to represent and how to write out the equation to the following word problem:

Mario collects a commission for bringing in advertisers to his magazine company. He receives 8% on $450 full-page ads and 5% for $300 half-page ads. If he sells twice as many half-page ads as full-page ads and his commission was $5610, how many of each type did he bring in?
thanks for the help!
1 solutions

Answer 116894 by scott8148(6628) About Me  on 2008-09-24 10:56:46 (Show Source):
You can put this solution on YOUR website!
let x="full-page", so 2x="half-page"

[(8%)(450)(x)]+[(5%)(300)(x)]=5610

remember that % gets changed to decimal


Polynomials-and-rational-expressions/158717: CAN SOMEONE PLEASE HELP ME WITH THIS PROBLEM:
Which of the folling is a sixth order equation?
1. S(x) = x^5 + x^6 - 2x +7
2. Q(x) = x^2 + 3^6
3. M(x) = (x^3)^3 - 12x + 4
4. None of the above
1 solutions

Answer 116893 by scott8148(6628) About Me  on 2008-09-24 10:50:30 (Show Source):
You can put this solution on YOUR website!
sixth order means that 6 is the largest exponent (for a variable)
__ looks like number 1


Polynomials-and-rational-expressions/158718: can someone please help me figure out this problem:
Which of the following pair of points is indicative of a zero per the Intermediate Value Theorem?
1. (0,0) & (2,-3)
2. (-2,-3) & (2,-3)
3. (2,0) & (0,-3)
4. (3,-4) & (-6,12)
1 solutions

Answer 116892 by scott8148(6628) About Me  on 2008-09-24 10:48:23 (Show Source):
You can put this solution on YOUR website!
the y value cannot change from -4 to 12 without going through zero, so 4 is the correct answer


Polynomials-and-rational-expressions/158722: can someone please help me figure this out?
Which of the following coefficients cannot be zero if p(x) is a parabola and of the form p(x) = Ax^2 + Bx + C?
1. A
2. B
3. C
4. None of the above, A, B, and C can each have the value of 0
1 solutions

Answer 116889 by scott8148(6628) About Me  on 2008-09-24 10:44:25 (Show Source):
You can put this solution on YOUR website!
if there is no 2nd order (squared) term, then the function is not a parabola
__ A cannot be zero

if B and/or C is zero, there is still a parabola
__ B moves the graph left-right
__ C moves the graph up-down


Percentage-and-ratio-word-problems/158569: Hi! I hope this is an acceptable use of this website. My husband has recently added a hydrogen generator to his engine to increase his gas mileage. He used to get 11 miles to a gallon but now he gets 18 miles to a gallon.
We can't seem to figure out how to come up with the percentage of increase that is. We will need to use this formula a lot since he will be building one for my SUV next and is considering helping others with them. It feels silly to not be able to figure this out. He used a calculator to come up with an answer and I used longhand division and multiplication by hand and the weird thing is that we came up with different answers. I double-checked mine so I know mine is correct but since I'm not sure I used the correct formula, I still feel unsure of my answer.
Thanks in advance for your help!
Susan
1 solutions

Answer 116814 by scott8148(6628) About Me  on 2008-09-23 11:53:12 (Show Source):
You can put this solution on YOUR website!
the increase from 11 to 18 is 7 __ the % increase is based on the original value

7 is 78% (approx) of the original value of 11 __ this is the percentage increase


Divisibility_and_Prime_Numbers/158559: Find the greatest 8 digit number you can divide by 1, 2, 3, and 4 without a remainder. (explain how you figured this out).
1 solutions

Answer 116812 by scott8148(6628) About Me  on 2008-09-23 11:48:04 (Show Source):
You can put this solution on YOUR website!
the smallest number divisible by 1, 2, 3, and 4 is 12 (3*4; 1 and 2 are factors of 4)

99999999 is the largest 8 digit number __ dividing by 12 leaves a remainder of 3

so the largest number is 99999999-3 or 99999996


Travel_Word_Problems/158561: This is a problem from a college algebra project, and we are stuck.
A motorist drove 150 miles on country roads before driving 50 miles on mountain roads. The rate of speed on the country roads was three times the rate on mountain roads. The time spent travelling the 200 miles was 5 hours. Find the rate of the motorist on country roads.
1 solutions

Answer 116810 by scott8148(6628) About Me  on 2008-09-23 11:40:41 (Show Source):
You can put this solution on YOUR website!
r*t=d __ t=d/r __ the total time is the sum of country time and mountain time

let x=country rate

[150/x]+[50/(x/3)]=5 __ multiplying by x __ 150+150=5x __ dividing by 5 __ 60=x


Polynomials-and-rational-expressions/158324: Consider the fractional problem:
x - 8 OVER x + 5 divided by x - 9 OVER x + 4
Explain to me why -5, 9 and -4 are not allowable replacements for the variable x.
thank you very much.
1 solutions

Answer 116697 by scott8148(6628) About Me  on 2008-09-22 08:40:18 (Show Source):
You can put this solution on YOUR website!
any of those values would result in division by zero, which is an undefined operation (BIG no-no)


Polynomials-and-rational-expressions/158328: 2, 4 Express this following rational expressions in lowest terms, please!
4x^2 - 12x - 40 OVER 2x^2 - 16x + 30
wow... need help! thanks.
1 solutions

Answer 116696 by scott8148(6628) About Me  on 2008-09-22 08:37:09 (Show Source):
You can put this solution on YOUR website!
factoring __ %284%28x-5%29%28x%2B2%29%29%2F%282%28x-5%29%28x-3%29%29

"cancelling" __ %282%28x%2B2%29%29%2F%28x-3%29


Word_Problems_With_Coins/158322: The average value of all the pennies, nickels, dimes and quarters in Bob's pocket is 20 cents. If he had one more quarter, the average would be 21 cents. How many dimes does he have?
Many thanks!
1 solutions

Answer 116694 by scott8148(6628) About Me  on 2008-09-22 08:30:30 (Show Source):
You can put this solution on YOUR website!
working in cents

let n=number of coins

"The average value of all the pennies, nickels, dimes and quarters in Bob's pocket is 20 cents" __ 20n

"If he had one more quarter, the average would be 21 cents" __ 20n+25=21(n+1)

20n+25=21n+21 __ 4=n

4 coins worth 80 cents means 3 quarters and a nickel
__ no pennies or dimes


Quadratic_Equations/158223: Can someone help me Please? I can't seem to figure this one out.
S=1/3nr^2h+4nrh solve for r
Any help would be so great. Thank you.
1 solutions

Answer 116676 by scott8148(6628) About Me  on 2008-09-22 00:18:53 (Show Source):
You can put this solution on YOUR website!
subtracting S __ 0=1/3nr^2h+4nrh-S

use quadratic formula to find r