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fractalier answered: 2101 problems
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y-2x=0
y=4x-1
What is the solution of the system of equations? 1 solutions
Answer 23686 by fractalier(2101) on 2006-05-17 10:55:38 (Show Source):
You can put this solution on YOUR website!From
y - 2x = 0
y = 4x - 1
I can show you the solution but graphing it here is impossible...
Normally you can set up an x-and-y chart and plug in values to get the points you plot...or you can put each line in slope-intercept form and graph...
In either case, the place where the lines intersect is your solution...
In this case, this is x = 1/2 and y = 1 or (1/2, 1)
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Linear_Equations_And_Systems_Word_Problems/37665: This question is from textbook
Safety Rent-a-Car rents an intermediate-size car at a daily rate of $21.95 plus .19 per mile. City Rentals rent an intermediate-size car for $18.95 plus .21 per mile. For what milage is the cost the same? 1 solutions
Answer 23685 by fractalier(2101) on 2006-05-17 10:51:04 (Show Source):
You can put this solution on YOUR website!Let x be the number of miles.
Then we convert the facts of the problem into algebra and get:
21.95 + .19x = 18.95 + .21x
Let us multiply everything by 100 to get rid of decimals...
2195 + 19x = 1895 + 21x
Now subtract 19 x from both sides
2195 = 1895 + 2x
Now subtract 1895 from both sides and then divide by two...
300 = 2x
x = 150 miles
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Graphs/38105: MATCH EACH SYSTEM WITH IT'S CORRECT SOLUTION.
2Y-8=X
2Y+2X=2
A. (3,2)
B.(3,3)
C. (-2,3)
D. (2,3) 1 solutions
Answer 23684 by fractalier(2101) on 2006-05-17 10:46:43 (Show Source):
You can put this solution on YOUR website!From
2Y - 8 = X
2Y + 2X = 2
let us substitute 2y - 8 for x in the second equation and get
2y + 2(2y - 8) = 2
2y + 4y - 16 = 2
6y - 16 = 2
6y = 18
y = 3
and then
x = 2y - 8
x = 2(3) - 8
x = -2
Choice C.
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Graphs/38172: Could you please help me with this one?
The equation of a line that contains the point (-2,4) and is parellel to y=2x-3. 1 solutions
Answer 23682 by fractalier(2101) on 2006-05-17 10:42:14 (Show Source):
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Radicals/38173: Please help!!
x=1+6 sqrt x-9
Thank you! 1 solutions
Answer 23677 by fractalier(2101) on 2006-05-17 10:30:59 (Show Source):
You can put this solution on YOUR website!Okay, from x = 1 + 6sqrt(x-9), move the one over first and get
x - 1 = 6sqrt(x-9)
Now square both sides
x^2 - 2x + 1 = 36(x - 9)
Now expand, combine, factor, solve and check...
x^2 - 2x + 1 = 36x - 324
x^2 - 38x + 325 = 0
(x - 13)(x - 25) = 0
x = 13 or x = 25
Both check out, so we have two solutions...
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Radicals/38202: Express the following expression in simplest radical form. All variables represent positive real numbers.
SQRT of (8y^3)/49x 1 solutions
Answer 23674 by fractalier(2101) on 2006-05-17 10:23:36 (Show Source):
You can put this solution on YOUR website!From sqrt(8y^3 / 49x), we will need to rationalize the denominator by multiplying by sqrt(x) / sqrt(x)...this will give us a perfect square in the denominator...
sqrt(8y^3 / 49x) =
sqrt(8y^3 / 49x) * [sqrt(x) / sqrt(x)] =
sqrt(8xy^3 / 49x^2)
We can pull perfect squares out of the radical from the numerator and denominator, giving us the answer...
sqrt(8xy^3 / 49x^2) =
(2y / 7x) * sqrt(2xy)
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Linear-equations/38179: Need some help
Find the equation of a line that contains the point (-2,4)and is parallel to
y=2x-3
thank you for your time. 1 solutions
Answer 23670 by fractalier(2101) on 2006-05-17 10:16:04 (Show Source):
You can put this solution on YOUR website!Parallel means same slope...so we need a line going thru (-2, 4) with a slope of 2...we use the point-slope formula...
y - y1 = m(x - x1)
y - 4 = 2(x -(-2))
y - 4 = 2(x + 2)
y - 4 = 2x + 4
y = 2x + 8
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Sequences-and-series/38187: Calculate the sum of all even positive integers from 2 to 4000. 1 solutions
Answer 23669 by fractalier(2101) on 2006-05-17 10:14:10 (Show Source):
You can put this solution on YOUR website!Gauss showed the shortcut for this hundreds of years ago, when he was but a child...
Notice that if you add the first and last terms you get 4002.
If you add the second and second-to-last terms you get 4002.
If you add the third and third-to-last terms you get 4002.
And so on, and so on...
Now how many pairs making 4002's are there?
Well, half the number of numbers present.
There are 2000 even numbers from 2 to 4000.
That means 1000 pairs, each adding to 4002.
So the sum is 1000 * 4002 = 4002000.
Cool!
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Radicals/38208: Express the following expression in simplest radical form. All variables represent positive real numbers.
SQRT of 27(a^2)b / SQRT of 7(a^3)(b^3) 1 solutions
Answer 23667 by fractalier(2101) on 2006-05-17 10:07:38 (Show Source):
You can put this solution on YOUR website!From
sqrt27(a^2)b / sqrt7(a^3)(b^3)
we can make it all one root and then cancel as possible, thus we get
sqrt[27(a^2)b / 7(a^3)(b^3)] =
sqrt[27 / 7ab^2]
From here, we need to rationalize the denominator by multiplying top and bottom by sqrt(7a)/sqrt(7a)...so we have
sqrt[27 / 7ab^2] * sqrt(7a)/sqrt(7a) =
sqrt[189a / 49(a^2)(b^2)]
Now 49(a^2)(b^2) is a perfect square so we can remove it from the root...our final answer is
sqrt(189a) / 7ab
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Quadratic_Equations/38203: Solve the quadratic equation by factoring and applying the property "ab=0 if and only if a=0 or b=0"
(x^2)-4x-21=0 1 solutions
Answer 23665 by fractalier(2101) on 2006-05-17 10:02:10 (Show Source):
You can put this solution on YOUR website!First we factor the trinomial
x^2 - 4x - 21 = 0
into its binomial factors:
(x - 7)(x + 3) = 0
Now if two quantities multiply together to make zero, one (or both) has to be zero...
Thus x - 7 = 0 and x + 3 = 0 which leads to
x = 7 or x = -3
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Money_Word_Problems/38110: Use the compound interest equation to find how long, to the nearest tenth of a year, it will take a $5000 investment to double if it is invested at 7% interest compounded quarterly. The answer is 10.0 years, I just can't figure out how to get it. 1 solutions
Answer 23611 by fractalier(2101) on 2006-05-16 16:53:11 (Show Source):
You can put this solution on YOUR website!Okay, from the equation
A = P(1 + r/n)^nt
we plug in what we know and solve for what we don't know...
10000 = 5000(1 + (.07/4))^4t
now divide by 5000
2 = (1 + (.07/4))^4t
take the log of both sides
log 2 = 4t*log(1 + (.07/4))
now solve for t...
t = log 2 / 4(log 1.0175)
t = 9.988 years or roughly 10 years
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Graphs/38082: Solve the system by addition
5x + 9y = -12
x - 2y = 10 1 solutions
Answer 23610 by fractalier(2101) on 2006-05-16 16:47:12 (Show Source):
You can put this solution on YOUR website!From
5x + 9y = -12
x - 2y = 10
let us multiply the bottom equation by (-5) and add it to the top one...
5x + 9y = -12
-5x + 10y = -50
which yields
19y = -62
and the not-so-nice
y = -62/19
Now plug that into the second equation to find x...
x - 2(-62/19) = 10
x + 124/19 = 10
x + 124/19 = 190/19
x = 66/19
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Divisibility_and_Prime_Numbers/38090: which of the following numbers are composit?
0, 1, 15, 19, 23, 31, 49, 55, 59, 87, 91, 97, 103, 105 1 solutions
Answer 23608 by fractalier(2101) on 2006-05-16 16:41:16 (Show Source):
You can put this solution on YOUR website!Those nmbers which can be factored into numbers other than itself and one are composite.
Thus, 15, 49, 55, 87, 91 and 105 are composite.
Aside from 0 and 1, the rest are prime.
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Graphs/38111: WHICH EQUATION IS PERPENDICULAR TO Y=4X+3?
A. Y=-4X-1
B. Y=-1/4X+2
C. Y=1/4X-6
D. Y=3X+9 1 solutions
Answer 23606 by fractalier(2101) on 2006-05-16 16:39:29 (Show Source):
You can put this solution on YOUR website!Perpendicular lines have slopes which are negative reciprocals of each other. thus we need a line with a slope of -1/4.
Choice B is correct.
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Parallelograms/38097: if a rhombus is inscribed in a circle, does that mean the diagonals would be congruent? 1 solutions
Answer 23603 by fractalier(2101) on 2006-05-16 16:35:57 (Show Source):
You can put this solution on YOUR website!Yes. Because the opposite angles would have to be equal to 90 degrees. Since you are given it is a rhombus, and not merely an arbitrary rectangle, it would have to be a square. Of course both squares and rectangles have congruent diagonals.
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Graphs/38109: MATCH EACH SYSTEM WITH THE CORRECT SOLUTION
X-Y=1
X=1/2Y+2
A. (3,2)
B. (3,3)
C.(-2,3)
D.(2,3) 1 solutions
Answer 23602 by fractalier(2101) on 2006-05-16 16:32:00 (Show Source):
You can put this solution on YOUR website!From
x - y = 1 and
x = (1/2)y + 2
Let us subtract 1/2y in the second one and then subtract equations..
x - y = 1
x - (1/2)y = 2
which leads to
-(1/2)y = -1
and
y = 2
plug that in the first eqn and get
x = 3
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Equations/38098: WHICH EQUATION IS PARALLEL TO Y=0.5X+1?
A. Y= 0.5X+1
B. Y=-0.5X+2
C. Y=0.5X-4
D. Y=X+1 1 solutions
Answer 23601 by fractalier(2101) on 2006-05-16 16:29:02 (Show Source):
You can put this solution on YOUR website!Parallel lines have equal slopes.
Thus which of the choices has a slope of .5?
Choice C is best. Choice is the exact same line and not technically parallel.
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Miscellaneous_Word_Problems/38106: A fish was caught whose tail weighed 9 pounds. His head weighed as much as his tail and half his body, and his body weighed as much as his head and tail. How much did the fish weigh? 1 solutions
Answer 23600 by fractalier(2101) on 2006-05-16 16:26:48 (Show Source):
You can put this solution on YOUR website!If the tail was 9 lbs, the head was 9 lbs too. If that was half the body, the body must have been 18 lbs, and the sum of head and tail, as stated...
Thus the entire fish, head, body and tail was 36 pounds. That's some fish!
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