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Functions/68123: Given f(x) = 5x^2 - 3x + 1, find f(-2).
a)-13
b)15
c)-25
d)27
I have tried to work this problem and just can't seem to find the f(-2) can someone please help with this. Thanks
1 solutions
Answer 48432 by Earlsdon(6291)   on 2007-01-26 17:03:09 (Show Source):
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Linear-equations/68090: I am helping my 13 year old with his homework. Please tell me what slope is and how it is measured in general. We are using an Egyptian pyramid as a model.
Thank you !
1 solutions
Answer 48382 by Earlsdon(6291) on 2007-01-25 21:47:35 (Show Source):
You can put this solution on YOUR website!Well, slope is defined as..."Rise over Run" which means that slope is a ratio (fraction, if you like) of the amount of rise divided by the distance from the base of the vertical height.
For example, if the pyramid's height is 250 meters (not sure if this is a realistic number) and the distance from the base of the verical line up through the center of the pyramid (this is called the height) is 200 meters, then the slope would be: Rise/Run = 250m/200m = 5/4
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Quadratic_Equations/68069: I have asked this question within the past two days without a response. I am having a tough time figuring out how to set this problem up. Once I know how to set it up and why, I can probably solve the equation. I hope someone out there can help me with this one, please.
Find two consecutive positive integers such that the sum of their squares is 85. [You must use algebra to solve this, setting up an equation with a variable, and using algebra to solve for the variable.]
1 solutions
Answer 48368 by Earlsdon(6291) on 2007-01-25 20:55:02 (Show Source):
You can put this solution on YOUR website!Let x be the first positive integer. The next consecutive positive integer would then be x+1.
The sum of the squares of these is 85.
 Simplify and solve for x.
 Simplify.
 Subtract 85 from both sides.
 Divide through by 2.
 Factor.
 Apply the zero product principle.
 and/or 
So, x = -7 and x = 6 Discard the negative value as the problem requires positive integers.
The two integers are: 6 and 7
Check:
 = 
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Rectangles/68061: The length of a rectangle is 2 cm more than twice its width. If the perimeter of the rectangle is 52 cm, find the dimensions of the rectangle.
1 solutions
Answer 48367 by Earlsdon(6291) on 2007-01-25 20:50:22 (Show Source):
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Square-cubic-other-roots/67962: Simplify:
sqrt 20 1
-------- - -------
5 sqrt 5
I have a few answers to choose from and this problem has lost me. Here are the answers:
A) 1/5 sqrt 5
B) Cannot be simplified
C) sqrt 20 - sqrt 5
-----------------
5
D) sqrt 20 - 5 sqrt 5
-----------------
sqrt 5
Thank you for your help!
1 solutions
Answer 48325 by Earlsdon(6291) on 2007-01-25 00:35:51 (Show Source):
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Mixture_Word_Problems/67898: This question is from textbook
How many gallons of a 5% acid solution must be mixed with 5 gal of a 10% solution to obtain a 7% solution?
1 solutions
Answer 48276 by Earlsdon(6291) on 2007-01-24 16:44:13 (Show Source):
You can put this solution on YOUR website!Let x = the required number of gallons of 5% acid solution.
You can write the equation from the problem description but first convert the percentages to their decimal equivalents.
5% of x + 10% of 5 = 7% of (x+5)
0.05(x) + 0.1(5) = 0.07(x+5) Simplify and solve for x.
0.05x + 0.5 = 0.35 + 0.07x Subtract 0.05x from both sides.
0.5 = 0.35+0.02x Subtract 0.35 from both sides.
0.15 = 0.02x Finally, divide both sides by 0.02
x = 7.5
You will need to add 7.5 gallons of 5% acid solution to 5 gallons of 10% acid solution to obtain 12.5 gallons of 7% acid solution.
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Linear_Equations_And_Systems_Word_Problems/67820: my problem is: Luke has $5.00 more than Sam, together they have $73.00. How much does each have. Explain the equation.
I know the answer is $34.00 and $39.00, but i don't know how to write it out.
Thank you
1 solutions
Answer 48218 by Earlsdon(6291) on 2007-01-23 21:47:39 (Show Source):
You can put this solution on YOUR website!Try this!
Let L = the amount that Luke has and S = the amount that Sam has. From the problem description, you can write:
L = S+$5 and
L+S = $73 Substitute here the L from above and solve for S.
(S+$5) + S = $73 Simplify.
2S+$5 = $73 Subtract $5 from both sides.
2S = $68 Divide both sides by 2.
S = $34
L = S+$5
L = $39
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Equations/67814: I am trying to solve and check can you help me where I am wrong.
5x+8+3x-x+5=6x-3
7x+13=6x-3
3x 3x
10x+13=9x-3
3 3
10x+16=9x
-9x -9x
x+16=0
-16 -16
x=-16
check
5x+8+3x-x+5=6x-3
-80+8-48+16+5=-96-3
-99=-99
1 solutions
Answer 48214 by Earlsdon(6291) on 2007-01-23 21:40:49 (Show Source):
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Coordinate-system/67743: Find the slope of any line perpendicular to the line through points (0, 5) and
(-3, -4).
I am at total loss.
1 solutions
Answer 48186 by Earlsdon(6291) on 2007-01-23 17:38:42 (Show Source):
You can put this solution on YOUR website!Well, first you must find the slope of the line that contains the two given points. You can use the slope formula:
 where: (x1, y1) = (0, 5) and (x2, y2) = (-3, -4)
 Simplify.
Now, you'll recall that perpendicular lines have slopes that are the negative reciprocal of each other.
The negative reciprocal of 3 is 
So the answer is.: the slope is 
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Quadratic_Equations/67738: I have a square field with an area x + 12 by x + 12. A section of it has been removed, and that area is x + 1 by x + 7. The area of the square minus the missing section is 217.
The equation is (x + 12)^2 - (x + 1)(x + 7) = 217.
I tried using the distributive property to get x^2 + 24x + 144 - x^2 + 8x + 7 = 217.
Then I get stuck. If I combine x^2 and -x^2, I no longer have a quadratic equation, (which is the section we're studying).
What should I do? Thanks for your help.
GJL
1 solutions
Answer 48185 by Earlsdon(6291) on 2007-01-23 17:18:40 (Show Source):
You can put this solution on YOUR website!If the problem is to solve for x, which this appears to be, then you are proceeding correctly, except for the results of applying the distributive property. I shouldn't be too concerned with not having a quadratic equation in the final stages. Solve for x.
 Simplify the left side.
 Continue simplifying.
 Subtract 137 from both sides.
 Finally, divide both sides by 16.
As you can see, the  's drop out so you no longer have a quadratic equation but you can still solve for x.
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Linear-systems/67732: Hello,
I have recently started learning about the systems of linear equations. I understand how to solve by graphing, substitution, and elimination but I have a question about a math problem.
I need to solve this system of linear equations algebraically using elimination:
3x-2y=9
-6x+4y=1
PLEASE HELP ME WITH THIS PROBLEM AS SOON AS POSSIBLE.I always work really hard in school but am confused on how to solve this problem and figure out what special system it is. PLEASE HELP ME!
Confused Algebra 1 student
1 solutions
Answer 48181 by Earlsdon(6291) on 2007-01-23 16:58:42 (Show Source):
You can put this solution on YOUR website!Solve by elimination:
1).  Multiply equation 1) by 2 and add to equation 2).
2). 
1a) 
---------------------
 This result indicates that there is no solution. The two lines are parallel and there is no intersection, thus no solution. The graph below clearly shows this.
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Trigonometry-basics/67533: If you are given values for two sides of an oblique triangle and an angle opposite one of them, how would you arrive at the values of the missing parts? Will this result in a unique triangle?
1 solutions
Answer 48049 by Earlsdon(6291) on 2007-01-22 00:42:51 (Show Source):
You can put this solution on YOUR website!Given the values of two sides of an oblique triangle ABC (one that does not contain a right angle) and an angle opposite one of them, how would you find the values of the missing parts?
Assume that we are given sides a and b and angle A
There are three cases to consider in this situation:
1. If angle A is acute and the length of side a lies between b and b sin A, then there will be two soltions.
2. If angle A is acute and the length of a < b sin A, or if if angle A is obtuse and a < b or a = b, then there is no solution.
3. For all other cases, there is one solution.
Let's consider case 3. We will be applying the law of sines:  =  = 
To find angle B:
 Solve for sin B
To find side c:
 Solvefor c.
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Geometry_Word_Problems/67480: An open-top box is to be constructed from a 4 ft by 6 ft rectangular cardboard by cutting out equal squares at each corner and folding up the flaps. Let x denote the length of each side of the square to be cut out.
Find the function V that represents the volume of the box in terms of x.
1 solutions
Answer 48002 by Earlsdon(6291) on 2007-01-21 17:19:01 (Show Source):
You can put this solution on YOUR website!The base of the new box, after the corners (x by x) have been removed, will have the dimensions (4-2x)ft. by (6-2x)ft. and the height of the box will be x ft.
The function, V, that represents the volume of the box will be:
 Simplifying this:
 or
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Miscellaneous_Word_Problems/67445: From each of the the 4 corners of a rectangular piece of cardboard 8 inches wide, and 12 inches long, a 2 inch square is cut off.
A) What is the area of the new figure?
B) If the 4 sides of the new figure are folded straight up to form a box that is open at the top, what is the volume of this box?
1 solutions
Answer 47993 by Earlsdon(6291) on 2007-01-21 13:46:27 (Show Source):
You can put this solution on YOUR website!A. Find the area of the original piece of cardboard: A = 8X12 = 96 sq.in.
Subtract the area of the 4 removed corners: 4(2X2) = 16 sq.in.
A. New area = (8X12) - 4(2X2) = 96 - 16 = 80 sq.in.
The volume of the newly-formed box is found by multiplying the old length less two of the corners: (12-2(2) = 12-4 = 8 in.) by the old width less two of the corners: (8-2(2) = 8-4 = 4) by the height of the box (2 in.)
B. V = (12-4)(8-4)(2) = 8X4X2 = 64 cu.in.
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Signed-numbers/67450: This question is from textbook
4. use the distributive property to rewrite each expression without parentheses.
A. 5 (7+6)
B. 15+7 (10+5)
C. 13-6 (9+4)
D. -3 (8+7)
E. 4-6 (8-12)
F. 6(4-9) + 7 (5+7)
1 solutions
Answer 47988 by Earlsdon(6291) on 2007-01-21 13:27:35 (Show Source):
You can put this solution on YOUR website!Rewrite, using the distributive property:
A. 5(7+6) = 5*7+5*6 = 36+30 = 65
B. 15+7(10+5) = 15+7*10+7*5 = 15+70+35 = 120
C. 13-6(9+4) = 13-(6*9+6*4) = 13-(54+24) = 13-78 = -65
D. -3(8+7) = -3*8 + (-3)*7 = -24 + (-21) = -45
E. 4-6(8-12) = 4-(6*8-6*12) = 4-(48-72) = 4-(-24) = 4+24 = 28
F. 6(4-9)+7(5+7) = (6*4-6*9) + (7*5+7*7) = (24-54)+(35+49) = (-30)+(84) = 54
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Percentage-and-ratio-word-problems/67436: Smart Cards have been growing in popularity in recent years. In 2006, 500 million Smart Cards are expected to be issued. This represents a 117% increase from the number of cards that were issued in 2001. How many Smart Cards were issued in 2001? Round to the nearest million.
I set it up as 1.17 · x + x = 500
multiplied all by 100 117 · 200x = 50000
subtracted 117 from both sides 200x = 49883
divided both sides by 200 x = 249.415
The books answer is 230 mil.
1 solutions
Answer 47986 by Earlsdon(6291) on 2007-01-21 11:08:34 (Show Source):
You can put this solution on YOUR website!You have set it up correctly but there is a little problem with the math.
If x represents the number of Smart Cards issued in 2001, then:
x + 1.17x = 500 (in millions) Simplifying this:
2.17x = 500 Multiplying both sides by 100.
217x = 50000 Divide both sides by 217
x = 230.4147...millions. Round to the nearest million.
x = 230 million.
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Coordinate-system/67440: Write the equation of the line with given slope and y-intercept. Then graph each line using
the slope and y-intercept.
slope;-3/4 and y intercept is (0,8)
I know that y=-3/4x+8
I need to know the rise and run.
Would the run be 4 or -4? Is the whole fraction negative or just the top?
1 solutions
Answer 47984 by Earlsdon(6291) on 2007-01-21 11:01:36 (Show Source):
You can put this solution on YOUR website!Well, you have the correct equation in the slope-intercept form:
The slope is  and, of course, slope is rise over run, so the rise is 3 and the run is 4.
The question of which part of the slope is negative is really irrelevant. The entire slope is negative which means that the line leans to the left.
One way to look at it is in drawing the line so that is has the correct slope, you would go up (rise) 3 units on the graph and then go left (run) -4 units. Why left and not right? Well, because the slope is negative (left-leaning) and not positive (right-leaning).
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Money_Word_Problems/67441: Zoya Lon invested part of her $25,000 advance at 8% annual simple interest and the rest at 9% annual simple interest. If her total yearly interest from both accounts was $2135, find the amount invested at each rate.
I'm having a problem setting this up as an equation using the formula
Int. = P · r · t
1 solutions
Answer 47980 by Earlsdon(6291) on 2007-01-21 10:50:09 (Show Source):
You can put this solution on YOUR website!Let's say that x dollars were in the 8% account and the rest ($25000-x) was in the 9% account.
So Zoya Lon received two interest ammounts that added up to $2135.00 for the year. You can set this up as follows using I = Prt: Where r1 = 8% or 0.08 and r2 = 9% or 0.09, P1 = x and P2 = $25000-x, and t = 1 year.
Note that two interest amounts I1 + I2 = $2135
I1 = x(0.08)(1) = 0.08x
I2 = ($25000-x)(0.09)(1) = $2250-0.09x
Now add I1 and I2
I1+I2 = 0.08x + ($25000-x)(0.09) = $2135 Simplify this and solve for x.
0.08x+$2250-0.09x = $2135
-0.01x+$2250 = $2135
-.01x = -$115 Divide both sides by -0.01
x = $11500 This is the amount invested at 8%
$25000-x = $25000-$11500 = $13500 This is the amount invested at 9%
Check:
0.08($11500) + 0.09($13500) = $920 + $1215 = $2135
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Square-cubic-other-roots/67439: A square root problem. Just simplify...Its dificult to write it so i uploaded a foto with the problem....
http://i141.photobucket.com/albums/r71/kracivi/untitled.png
1 solutions
Answer 47979 by Earlsdon(6291) on 2007-01-21 10:15:08 (Show Source):
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