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expressions/39315: simplify 4x-5(x-7) a -x + 35 b) -x-35 c) -x-7 d) 9x+35
1 solutions

Answer 24996 by fractalier(2101) About Me  on 2006-05-26 12:27:07 (Show Source):
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4x - 5(x-7) =
4x - 5x + 35 =
-x + 35
Choice a.


expressions/39538: Simply each of the following expressions where possible (pg. 150)

I can't really type it out on my computer but the numbers are on the left side of the letter.
6x2y3 + 9x2y3
________________________________
3x2y2
1 solutions

Answer 24995 by fractalier(2101) About Me  on 2006-05-26 12:24:27 (Show Source):
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From
(6x^2y^3 + 9x^2y^3) / 3x^2y^2
we can combine the numerator and cancel where we can...we get
(6x^2y^3 + 9x^2y^3) / 3x^2y^2 =
15x^2y^3 / 3x^2y^2 =
5y


Equations/39428: 2y/x^2+2x+1 + x/x^2-1
1 solutions

Answer 24993 by fractalier(2101) About Me  on 2006-05-26 12:21:56 (Show Source):
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We factor denominators first and get
2y/x^2+2x+1 + x/x^2-1 =
2y / (x+1)^2 + x / (x+1)(x-1)
The lowest common denominator is then
(x-1)(x+1)^2
We convert both fractions to that denominator and combine and get
2y / (x+1)^2 + x / (x+1)(x-1) =
2y(x-1) / (x-1)(x+1)^2 + x(x+1) / (x-1)(x+1)^2 =
[2y(x-1) + x(x+1)] / (x-1)(x+1)^2 =
No further significant simplification can be done...


Rational-functions/39541: The cost of producing a number of items x is given by C=mx+b, in which b is the fixed cost and m is the variable cost (the cost of producing one more item).
(a) if the fixed cost is $40 and the variable cost is $10, write the cost equation.
(b) Graph the cost equation
1 solutions

Answer 24991 by fractalier(2101) About Me  on 2006-05-26 12:17:15 (Show Source):
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To get the cost equation, just plug in for m and b to get
C = 10x + 40
To graph it, go to the point (0, 40) and plot a point.
From that point, we have a slope of 10. We go up 10 and over 1, and plot another point. Then draw a line thru the points.


Rational-functions/39542: Find the slope of the line through the given points.
(2,4)and (6,-3)
1 solutions

Answer 24989 by fractalier(2101) About Me  on 2006-05-26 12:14:59 (Show Source):
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slope m is found by
m = (y2 - y1) / (x2 - x1)
m = (-3 - 4) / (6 - 2)
m = -7/4


Trigonometry-basics/39543: why should we take sin theta as opposite/hypotenuse is there any proof for it can u please send it to me on my email address
1 solutions

Answer 24987 by fractalier(2101) About Me  on 2006-05-26 12:12:49 (Show Source):
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It is merely how we define the term sin(theta). It is not a proof, it is a definition.


Rational-functions/39544: find the constant of variation k.
m varies directly with n; m=144 when n=8
1 solutions

Answer 24986 by fractalier(2101) About Me  on 2006-05-26 12:11:43 (Show Source):
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We write the direct variation as
m = kn
then plug in m and n
144 = 8k
and thus
k = 16


Probability-and-statistics/39324: what measure is always the same as the
a. 50th percentile?
b. 25th percentile?

c. 75th percentile?
1 solutions

Answer 24978 by fractalier(2101) About Me  on 2006-05-26 10:33:10 (Show Source):
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In statistics, the 50th percentile corresponds to the median, the 25th percentile is the 1st quartile, and 75th percentile is the 3rd quartile...


logarithm/39444: Solve 2/3^2x = 12.
1 solutions

Answer 24977 by fractalier(2101) About Me  on 2006-05-26 10:28:06 (Show Source):
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It is not clear exactly what the problem is but I assume you mean
2 / (3^2x) = 12
I will show you this one...if you meant something else, please repost...
Okay, from
2 / (3^2x) = 12
we can rearrange the terms and get
3^2x = 2/12 = 1/6
take the log of both sides
log 3^2x = log 1/6
now use the power rule
2x log 3 = - log 6
and
x = (- log 6) / (2 log 3)


Equations/39470: Solve each equation. identify each equation as a conditional equation, an inconsistent equation, or an identity.
1/2b - 1/2=1/4b
1 solutions

Answer 24976 by fractalier(2101) About Me  on 2006-05-26 10:22:40 (Show Source):
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Let us multiply all by 4b to clear the fractions, so we get
1/2b - 1/2 = 1/4b
4b[1/2b - 1/2 = 1/4b]
2 - 2b = 1
now subtract 2, then divide by -2 and get
-2b = -1
b = 1/2
Must be a conditional equation, since an inconsistent equation has no solution, and an identity has an infinite number of solutions...


Sequences-and-series/39510: write out the term of the geometric sequence that satisfies the given conditions.
a1=-9,r=-9/10,n=5
1 solutions

Answer 24975 by fractalier(2101) About Me  on 2006-05-26 10:16:53 (Show Source):
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Okay, our first tern is -9. After that, we just multiply each term by the common ratio, which is in this case -9/10, until we get 5 terms...so we get
-9
81/10
-729/100
6561/1000
-59049/10000


Linear-systems/39511: solve the equation
6-17/z -3/z^2=0
1 solutions

Answer 24974 by fractalier(2101) About Me  on 2006-05-26 10:14:20 (Show Source):
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Let us clear fractions by multiplying all by z^2, so from
6 - 17/z - 3/z^2 = 0 we get
6z^2 - 17z - 3 = 0 which we can factor into
(6z + 1)(z - 3) = 0 and solve, giving us
z = -1/6 and z = 3


absolute-value/39535: One of our sample problems is.. and i'm lost:

Identify the property that is used

5 (6+7)=5+ (7+6)
1 solutions

Answer 24973 by fractalier(2101) About Me  on 2006-05-26 10:10:44 (Show Source):
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I imagine that you meant to write
5 + (6 + 7) = 5 + (7 + 6)
If that is the case, then we are demonstrating the commutative property of addition, a property which states that order doesn't matter when we add numbers...


Average/39534: Question:
6.(5+4) =

What I'm thinking:
I'm thinking it is 6 times 9 = 54
1 solutions

Answer 24972 by fractalier(2101) About Me  on 2006-05-26 10:08:16 (Show Source):
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Yes. If the period after the six represents multiplication, as in
6*(5+4) = 6*9 = 54


Geometric_formulas/39514: The quotient when 3 more than a number is divided by less than that same number

Write each of the following geometric expressions using the given symbols

If you can please help me.I got this problem wrong,and I would like to know how to do it correct. Thank you
1 solutions

Answer 24971 by fractalier(2101) About Me  on 2006-05-26 10:06:35 (Show Source):
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Just posted this solution...


Travel_Word_Problems/39532: The quotient when 3 more than a number is dived by 3 less than that same number. Write each of the following geometric expressions using the given symbols
1 solutions

Answer 24970 by fractalier(2101) About Me  on 2006-05-26 10:05:41 (Show Source):
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Just posted this solution...


Length-and-distance/39533: The quotient when 3 more than a number is divided by 3 less than that same number. Write each of the following geometric expressions using the given symbols
1 solutions

Answer 24969 by fractalier(2101) About Me  on 2006-05-26 10:03:41 (Show Source):
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Let the unknown number be x. Then we have
(x + 3) / (x - 3)


absolute-value/39530: The sum m & n ,divided by the difference m & n
1 solutions

Answer 24968 by fractalier(2101) About Me  on 2006-05-26 10:02:22 (Show Source):
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Just posted this solution...


absolute-value/39531: The sum m & n ,divided by the difference of m & n
1 solutions

Answer 24967 by fractalier(2101) About Me  on 2006-05-26 10:01:30 (Show Source):
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You would express this as
(m + n) / (m - n)


Equations/39515: It is estimated that the Earth is losing 4000 species of plants and animals per year. If S represents the number of species living last year year, how many species are on Earth this year..
1 solutions

Answer 24966 by fractalier(2101) About Me  on 2006-05-26 10:00:49 (Show Source):
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Just posted this solution...


Functions/39517: It is estimated that the Earth is losing 4000 species of plants and animals per year. If S represents the number of species living last year year, how many species are on Earth this year..
1 solutions

Answer 24965 by fractalier(2101) About Me  on 2006-05-26 09:57:57 (Show Source):
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Look at it this way...
No matter how many species there were last year, you would be subtracting 4000 to get this year's number...if there were 90,000 last year, you'd have 86,000 this year...
Thus if there were S species last year, there would be S - 4000 this year...


Inequalities/39518: This question is from textbook
. Fill in the chart given this linear equation:
2x + y = 42.
x y
-2
-1
0
1
2
1 solutions

Answer 24964 by fractalier(2101) About Me  on 2006-05-26 09:55:47 (Show Source):
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Just posted this solution...


Travel_Word_Problems/39529: Suppose that the tempature outside is dropping at a constant rate.At noon, the tempature is 70 F,and it drops to 58F at 5pm ..How much did the tempature change each hour?

I thought it was half hour ,but i was wrong.Sorry the 5 did not come up in my other post.
1 solutions

Answer 24963 by fractalier(2101) About Me  on 2006-05-26 09:55:13 (Show Source):
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Well, we can logic it out...
If the temperature drops from 70 to 58, it dropped 12 degrees.
If it took 5 hours, then we divide 12 degress by 5 hours, and get
12 / 5 = 2.4 degrees per hour
We can look at it another way too...
(70 - 58) / (5 - 0) = 2.4


Inequalities/39527: This question is from textbook
Fill in the chart given this linear equation:
2x + y = 42.
x y
-2
-1
0
1
2
1 solutions

Answer 24962 by fractalier(2101) About Me  on 2006-05-26 09:51:53 (Show Source):
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To fill in these values, merely substitute the various x's into the equation and determine the y's...
2x + y = 42
x_____y
-2____46
-1____44
0_____42
1_____40
2_____38
See the pattern? Linear equations are always like this...


Inequalities/39528: This question is from textbook
1. Solve for x:
2(x + 3) > 20
1 solutions

Answer 24961 by fractalier(2101) About Me  on 2006-05-26 09:49:31 (Show Source):
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We wish to isolate x by "undoing" that which is being done to it...so from
2(x + 3) > 20
divide by 2 and get
x + 3 > 10
and subtract 3
x > 7
and we're done.


Numbers_Word_Problems/39408: The sum of two numbers is 100. One number is 5 less than twice the other. Find the numbers.
1 solutions

Answer 24884 by fractalier(2101) About Me  on 2006-05-25 18:10:11 (Show Source):
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Let the two numbers be x and y.
Thus
x + y = 100
and
x = 2y - 5
Now substitute for x in the first equation and get
2y - 5 + y = 100
3y - 5 = 100
3y = 105
y = 35 and since they add to 100,
x = 65


Rational-functions/39438: what's the answer to this problem? 10y2+15y divded by 35y2-5y
(the 2's beside the y's mean the y's are squared)
1 solutions

Answer 24881 by fractalier(2101) About Me  on 2006-05-25 17:59:42 (Show Source):
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(10y^2 + 15y) / (35y^2 - 5y)
we can factor both and get
(10y^2 + 15y) / (35y^2 - 5y) =
5y(2y + 3) / 5y(7y - 1)
now notice the 5y's cancel, leaving us
(2y + 3) / (7y - 1)


Polynomials-and-rational-expressions/39451: how do you rationalize(sqrt x+5)-3/ x-4?
1 solutions

Answer 24880 by fractalier(2101) About Me  on 2006-05-25 17:57:36 (Show Source):
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Normally when we use the term rationalize, it usually refers to a denominator that is irrational or complex, but the way you have given the expression,
(sqrt x+5)-3/ x-4
it appears that the numerator is irrational. This is acceptable the way it is.
If we try to rationalize it, the denominator will become irrational and unacceptable.


logarithm/39441: Solve e^2x = 5.
1 solutions

Answer 24878 by fractalier(2101) About Me  on 2006-05-25 17:52:35 (Show Source):
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From e^2x = 5
take the ln of both sides
ln e^2x = ln 5
2x = ln 5
x = (1/2)ln 5


logarithm/39443: Solve -4e^2x + 3 = -5
1 solutions

Answer 24875 by fractalier(2101) About Me  on 2006-05-25 17:09:11 (Show Source):
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From -4e^2x + 3 = -5
subtract three, then divide by minus four...
-4e^2x = -8
e^2x = 2
take ln
2x = ln 2
x = (1/2)*ln 2


Travel_Word_Problems/39410: A cyclist rode 1 mile in 3 minutes with the wind and returned in 4 minutes against the wind. Find his speed without the wind.
1 solutions

Answer 24867 by fractalier(2101) About Me  on 2006-05-25 13:39:59 (Show Source):
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The equation we use in these problems is D = RT, distance = rate times time.
With the wind, D = 1, T = 3 and his rate is R + w, w being the wind.
Against it, D = 1, T = 4, and his rate is R - w.
So we have
3(R + w) = 1
4(R - w) = 1
from which we get
(R + w) = 1/3
(R - w) = 1/4
adding equations we get
2R = 7/12
and
R = 7/24 miles per minute = 60(7/24) = 17.5 miles per hour