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Numeric_Fractions/38821: This question is from textbook Saxon
I need with this problem please 1 1/3x-3 1/2=41/18
1 solutions

Answer 24372 by fractalier(2101) About Me  on 2006-05-22 12:16:52 (Show Source):
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Okay from
1 1/3x-3 1/2=41/18, let us rewrite it in improper fractions
(4/3)x - 7/2 = 41/18
If I multiply everything by the lowest common denominator, 18, I can cleasr all fractions...thus
18[(4/3)x - 7/2 = 41/18]
24x - 63 = 41
now add 63 and divide by 24
24x = 104
x = 104/24 = 13/3


Expressions-with-variables/38859: using elimination to solve this system of equations, how would i solve
8x-3y=-11
2x-5y=27
1 solutions

Answer 24371 by fractalier(2101) About Me  on 2006-05-22 12:13:28 (Show Source):
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From
8x - 3y = -11
2x - 5y = 27
let us multiply the second equation by 4 and subtract it from the first, thus eliminating the x's...
8x - 3y = -11
-(8x - 20y = 108)
and we get
17y = -119
y = -7
and then by substituting we get
2x - 5(-7) = 27
2x + 35 = 27
2x = -8
x = -4


Linear-equations/38873: PLease help me write the equation of the line with x-intercept (3, 0) and y-intercept (0, 2).
Thank You
1 solutions

Answer 24370 by fractalier(2101) About Me  on 2006-05-22 12:01:47 (Show Source):
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There is a special form of a line not taught very often called the intercept form and it goes like this
x/a + y/b = 1
where a and b are the x- and y-intercepts...
Here we have such a case and so
x/3 + y/2 = 1
now multiply by 6 and get
2x + 3y = 6


Quadratic-relations-and-conic-sections/38917: x^2+y^2-16x+4Y+59=0 what is this put in standard form and graphed
1 solutions

Answer 24369 by fractalier(2101) About Me  on 2006-05-22 11:54:41 (Show Source):
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Let us rearrange and coomlete the square twice, so from
x^2 + y^2 - 16x + 4y + 59 = 0 we get
x^2 - 16x + 64 + y^2 + 4y + 4 = -59 + 64 + 4
(x - 8)^2 + (y + 2)^2 = 9
This is a circle with center at (8, -2) and radius 3.


Geometry_Word_Problems/38897: The height of a triangle is twice the base. The area is 9 square inches. find the area.
1 solutions

Answer 24368 by fractalier(2101) About Me  on 2006-05-22 11:32:32 (Show Source):
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The area is given as 9 -- is that what they really want? I doubt it...
The facts they give us are
h = 2b
and
A = 9
but we know that
A = (1/2)bh
so now substitute in everything and get
9 = (1/2)b(2b)
b^2 = 9
b = 3
Then h = 6.
This is probably what they wanted.


Radicals/38914: x+2/x + 1/3 = 2
1 solutions

Answer 24367 by fractalier(2101) About Me  on 2006-05-22 11:28:54 (Show Source):
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From x+2/x + 1/3 = 2, we multiply all by 3x to clear fractions
(x+2)/x + 1/3 = 2
3(x+2) + x = 6x
3(x+2) = 5x
x + 2 = 5x/3
now subtract off x (which is 3x/3)
2 = 2x/3
x = 3


Exponents/38915: This question is from textbook
what is the equivalent to 7a/15b-2b/5
1 solutions

Answer 24366 by fractalier(2101) About Me  on 2006-05-22 11:25:32 (Show Source):
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From 7a/15b-2b/5 we will multiply the second fraction by 3b/3b to have common denominators...thus
7a/15b - (2b/5)(3b/3b) =
7a/15b - 6b^2/15b =
(7a - 6b^2) / 15b


Radicals/38912: (3radical a - 2 radical b) (3radical + 2radical b)
1 solutions

Answer 24365 by fractalier(2101) About Me  on 2006-05-22 11:23:22 (Show Source):
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If you mean
(3rad(a) - 2rad(b)) * (3rad(a) + 2rad(b))
then you have a sum times a difference which equals the difference of their squares, so you get
[3rad(a)]^2 - [2rad(b)]^2 =
9a - 4b


Equations/38906: solve for t
P = 2pt/t+4

(P equals 2pt over t+4) solve for t
1 solutions

Answer 24364 by fractalier(2101) About Me  on 2006-05-22 11:20:27 (Show Source):
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From
P = (2pt) / (t + 4)
and assuming that P and p are different variables, multiply both sides by t + 4
P(t + 4) = 2pt
Pt + 4P = 2pt
now collect terms with t in them
Pt - 2pt = -4P
t(P - 2p) = -4P
t = -4p / (P - 2p)
If P and p are meant to be the same, then
t = 4


Quadratic-relations-and-conic-sections/38909: What is ysquared-4y-4x=0 put in standard form and graphed
1 solutions

Answer 24363 by fractalier(2101) About Me  on 2006-05-22 11:14:14 (Show Source):
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From
y^2 - 4y - 4x = 0
we complete the square, also add 4x to both sides
y^2 - 4y + 4 = 4x + 4
(y - 2)^2 = 4(x + 1)
now divide by four and subtract one and get
(1/4)(y - 2)^2 = x + 1
x = (1/4)(y - 2)^2 - 1
This is a wider-than-normal parabola, concave right, with vertex at (-1, 2).


Quadratic-relations-and-conic-sections/38910: 4xsquared+25ysquared-100=0 put in standard form and graphed
1 solutions

Answer 24362 by fractalier(2101) About Me  on 2006-05-22 11:07:08 (Show Source):
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From
4x^2 + 25y^2 - 100 = 0
add 100 and then divide by 100
4x^2 + 25y^2 = 100
x^2 / 25 + y^2 / 4 = 1
This is an ellipse with semi-major axis of 5 and semi-minor axis of 2.
Intercepts at (5, 0), (-5, 0), (0, 2) and (0, -2).


Linear-equations/38741: 3x + 2y = 16
2x + y = 9
1 solutions

Answer 24334 by fractalier(2101) About Me  on 2006-05-21 20:55:25 (Show Source):
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From
3x + 2y = 16
2x + y = 9
solve the second equation for y and substitute it into the first equation...
y = -2x + 9
then
3x + 2(-2x + 9) = 16
3x - 4x + 18 = 16
-x = -2
x = 2
then
y = -2(2) + 9
y = 5


Polynomials-and-rational-expressions/38744: Please help!
Solve.
(x/x-9) - 4 = (9/x-9)
thanks
1 solutions

Answer 24333 by fractalier(2101) About Me  on 2006-05-21 20:52:04 (Show Source):
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Form (x/x-9) - 4 = (9/x-9) we multiply all by (x-9) to clear fractions and get
x - 4(x - 9) = 9
x - 4x + 36 = 9
-3x = -27
x = 9
but notice x is not allowed to be nine...the denominators would go to zero....therefore there is No Solution.


Divisibility_and_Prime_Numbers/38857: Can someone help me solve this problem?
Julio works as a quality control expert in a beverage factory. The assembly line that he monitors produces about 20,000 bottles in a 24-hour period. Julio samples about 120 bottles an hour and rejects the line if he finds more than 1/50 of the sample to be defective. About how many defective bottles should Julio allow before rejecting the entire line?
Thanks!
Sher
1 solutions

Answer 24332 by fractalier(2101) About Me  on 2006-05-21 20:49:42 (Show Source):
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Well 1/50 of 120 bottles is 2.4 bottles...therefore he can allow two defective ones per hour before rejecting the whole line...the 3rd bad one and it's over...


expressions/38856: evaluate the following expression
ab to the negative 1st power over c
1 solutions

Answer 24330 by fractalier(2101) About Me  on 2006-05-21 20:46:24 (Show Source):
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Okay from
a(b^-1) / c
we know that negative exponents on the top become positive exponents on the bottom, so this becomes
a / bc.
If the original problem was (ab)^-1 / c (it is not clear), then your answer is
1/abc


Geometry_Word_Problems/38791: The hypotenuse of a right triangle is 4 cm. longer than one leg and 18 cm. longer than teh other leg. Find te lenght of each side of the triangle.
1 solutions

Answer 24329 by fractalier(2101) About Me  on 2006-05-21 20:44:25 (Show Source):
You can put this solution on YOUR website!
Just posted this solution...scroll thru my solutions...


Triangles/38788: The hypotenuse of a right triangle is 4 cm. longer than the one leg and 18 cm. longer than the other leg. Find the length of each side of the triangle.
1 solutions

Answer 24328 by fractalier(2101) About Me  on 2006-05-21 20:43:45 (Show Source):
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Call the shortest leg x.
The hypotenuse is x + 18.
The other leg is x + 14 since it is only 4 less than the hypotenuse.
Now apply the Pythagorean Theorem: a^2 + b^2 = c^2 and we get
x^2 + (x + 14)^2 = (x + 18)^2
x^2 + x^2 + 28x + 196 = x^2 + 36x + 324
now collecting and solving we get
x^2 - 8x - 128 = 0
(x - 16)(x + 8) = 0
x = 16 or x = -8
but distance is never negative so the short leg is 16 and the longer leg is 30. The hypotenuse is 34.


Quadratic-relations-and-conic-sections/38794: Find the center and radius of x^2+y^2-6x-2y-6=0
This is non from a text book
1 solutions

Answer 24327 by fractalier(2101) About Me  on 2006-05-21 20:39:29 (Show Source):
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From x^2+y^2-6x-2y-6=0 we complete the squares...
x^2 - 6x + ___ + y^2 - 2y + ___ -6 = 0 + ___ + ___
x^2 - 6x + 9 + y^2 - 2y + 1 = 6 + 9 + 1
(x - 3)^2 + (y - 1)^2 = 16
center at (3, 1) and radius = 4


Rational-functions/38843: This question is from textbook Elementary Algebra
I need help simplifying this problem:
6-x over x-6 (divison)
1 solutions

Answer 24326 by fractalier(2101) About Me  on 2006-05-21 20:36:42 (Show Source):
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This is an important fact in algebra...NO MATTER what the two quantities are (aside from a zero denominator),
(x - y) / (y - x) = -1
Negative One!
So (6-x) / (x-6) is, you guessed it!
-1


Polynomials-and-rational-expressions/38853: This question is from textbook Beginning Algebra
Okay, I added, but am having trouble simplifiying...
could you please help me?
This is what I have so far...

   x²       3x - 70
———————— + —————————
 x + 10      x + 10

I got   

   x² + 3x - 70
  ——————————————
      x + 10

how do I simplify that?
Thank you in advance for your help.

1 solutions

Answer 24325 by fractalier(2101) About Me  on 2006-05-21 20:34:25 (Show Source):
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Okay from
x^2 / x+10 + 3x-70 / x+10
we can add the numerator as they are since the denominators are the same, or what are called "like" denominators, so we simply get
(x^2 + 3x - 70) / (x + 10)
Now we factor the numerator and get
(x + 10)(x - 7) / (x + 10)
oh, what a surprise, the x + 10's cancel, leaving
the answer: x - 7


Polynomials-and-rational-expressions/38855: This question is from textbook Beginning Algebra
Okay, I don't even know where to begin with this one...
Subtract
5/y-7 minus 1/y+1
Please help me !! LOL
1 solutions

Answer 24323 by fractalier(2101) About Me  on 2006-05-21 20:31:25 (Show Source):
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I teach my students a method called the "criss-cross" method...
Whenever you have fractions like this you can apply a short-cut...
Goes like this...
A/B + C/D = (AD + BC) / BD
no matter what A, B, C, and D are and it works for adding or subtracting...
so from
5/(y-7) - 1/(y+1)
we criss cross and get
[5(y + 1) - (y - 7)] / [(y - 7)(y + 1)] =
5y + 5 - y + 7 / [(y - 7)(y + 1)] =
4y + 12 / [(y - 7)(y + 1)]
and we're done...


Miscellaneous_Word_Problems/38574: It takes Tom 4 hours to build a fence. If he hires Jack to help him, together they can do the job in just 3 hours. If jack built the same fence by himself, how long would it take him??
Thanks for answering!:-)
1 solutions

Answer 24112 by fractalier(2101) About Me  on 2006-05-19 17:10:33 (Show Source):
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We use the work problem formula
t/A + t/B = 1
t = time worked together
A = first guy's time alone
B = second guy's time alone
1 = one job or task
so plug in and get
3/4 + 3/B = 1
multiply all by 4B and get
3B + 12 = 4B
and
B = 12 hours


Miscellaneous_Word_Problems/38577: A vending machine has $41.25 in it. There are 255 coins total and the machine only accepts nickels, dimes and quarters. There are twice as many dimes and nickels. How many of each coin are in the machine?
1 solutions

Answer 24110 by fractalier(2101) About Me  on 2006-05-19 17:07:57 (Show Source):
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I have solved this one already. Please scroll through my solutions.


Polynomials-and-rational-expressions/38590: What values for x must be excluded in the following fraction?
x-3/(4x-5)(x+1)
1 solutions

Answer 24108 by fractalier(2101) About Me  on 2006-05-19 17:06:25 (Show Source):
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Any value that makes the denominator go to zero...that is if
4x - 5 = 0 or x + 1 = 0, we must exclude that value for x.
Thus x cannot be 5/4 or -1. We say these are excluded from the domain of x.


Polynomials-and-rational-expressions/38591: I previously asked this and no one answered. Please help!!
Add. Express answer in simplest form
4x/x^2-18x+72 + 4/x-6
1 solutions

Answer 24107 by fractalier(2101) About Me  on 2006-05-19 17:04:45 (Show Source):
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From
4x/)x^2-18x+72) + 4/(x-6)
we factor the denominator of the first fraction and get
4x/(x-12)(x-6) + 4/(x-6)
Notice that if we multiply the second fractaion by (x-12)/(x-12), we will have common denominators...so
4x/(x-12)(x-6) + 4(x-12)/(x-6)(x-12) =
(4x + 4x - 48) / (x-6)(x-12) =
8x-48 / (x-6)(x-12) =
8(x-6) / (x-6)(x-12) =
8 / (x-12)


Polynomials-and-rational-expressions/38587: I do not understand.
x+2 over x over x-2 over 3x
(x+2/x) / (x-2)/3x
Please help!
1 solutions

Answer 24101 by fractalier(2101) About Me  on 2006-05-19 16:34:18 (Show Source):
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From (x+2)/x / (x-2)/3x
we invert the denominator and then multiply and get
(x+2)/x * (3x/(x-2)
All that cancels are the x's, leaving
3(x+2) / x-2


Miscellaneous_Word_Problems/38578: Terry has 7 more quarters than dimes and has a total of $6.80. The number of quarters and dimes is 38. How many quarters and dimes does terry have?
Thanks for answering!:-)
1 solutions

Answer 24091 by fractalier(2101) About Me  on 2006-05-19 15:28:30 (Show Source):
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Let q = # of quarters. Thus their value is 25q.
Let d = # of dimes. Thus their value is 10d.
From the facts in the problem, we have
q + d = 38
25q + 10d = 680 ($6.80 expressed in cents)
We also have a third equation, not common in these problems (q = d + 7) which incidentally is impossible...
Let us solve the first for d and substitute into the second equation...
d = 38 - q
25q + 10(38 - q) = 680
25q + 380 - 10q = 680
15q = 300
q = 20 and then
d = 18


Miscellaneous_Word_Problems/38575: The mat around a picture measures x inches across. The length of the picture with the mat is 40 inches, and the width of the picture with its mat is 24 inches. If the area of the picture is 192 square inches, find the dimensions of the picture.
Thanks for answering!:-)
1 solutions

Answer 24089 by fractalier(2101) About Me  on 2006-05-19 15:22:30 (Show Source):
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Since the border all along the picture is x, the length of just the picture is
40 - 2x (since x on top and bottom).
The width is then 24 - 2x, by the same logic.
And of course, A = LW = 192.
So, by substituting, we get
192 = (40 - 2x)(24 - 2x)
192 = 960 - 128x + 4x^2 or
4x^2 - 128x + 768 = 0
x^2 - 32x + 192 = 0
(x - 24)(x - 8) = 0
x = 24 or x = 8
but the border cannot be 24, that's too big.
So the border is 8 inches, and the dimensions of just the picture are
40 - 16 = 24 inches
by
24 - 16 = 8 inches


Radicals/38572: 36. Show a complete solution.
Two positive numbers differ by 11, and their square roots differ by 1. Find the numbers.

1 solutions

Answer 24086 by fractalier(2101) About Me  on 2006-05-19 15:05:26 (Show Source):
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Let the numbers be x and y.
Then from the facts, we have
x - y = 11
sqrt(x) - sqrt(y) = 1
Let us solve the first one for x:
x = y + 11
Let us substitute that into the second equation.
sqrt(y + 11) - sqrt(y) = 1
We can rearrange this and then square both sides.
sqrt(y + 11) = sqrt(y) + 1
y + 11 = y + 2*sqrt(y) + 1
10 = 2*sqrt(y)
sqrt(y) = 5
y = 25
Thus x equals 36.


Coordinate-system/38544: how is y=5x+6 similar to -18x+3y=-54
1 solutions

Answer 24085 by fractalier(2101) About Me  on 2006-05-19 15:00:41 (Show Source):
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Well the first line is y = 5x + 6 and the
second line is y = 6x - 18 (when simplified)
They are both lines with positive slopes.
They share the point (24, 126) is common, that is, they intersect there.


Quadratic_Equations/38560: I need your help to solve this problem and also what are the steps to solve this problem.
The length of a hypotenuse of a right triangle is 2 feet more than the longer leg. The length of the longer leg is 7 feet more than the lenth of the shorter leg. Find the number of feet in length of each side of the right triangle.

1 solutions

Answer 24084 by fractalier(2101) About Me  on 2006-05-19 14:55:10 (Show Source):
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For every right triangle, a^2 + b^2 = c^2...
Let x = the length of the shorter leg.
Thus x + 7 is the longer leg and
x + 9 is the length of the hypotenuse...
So substituting into the Pythagorean Theorem, we have
x^2 + (x + 7)^2 = (x + 9)^2
x^2 + (x^2 + 14x + 49) = x^2 + 18x + 81
now collect like terms and solve for x
2x^2 + 14x + 49 = x^2 + 18x + 81
x^2 - 4x - 32 = 0
(x - 8)(x + 4) = 0
x = 8 and x = -4
but distances cannot be negative, so
x = 8
The other sides must be 15 and 17.