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Earlsdon answered: 6281 problems
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Polynomials-and-rational-expressions/51648: how do you factor a problem such as: a-squared - b-squared + 6b - 9?
1 solutions

Answer 34451 by Earlsdon(6287) About Me  on 2006-09-10 19:10:08 (Show Source):
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Factor: a%5E2-b%5E2%2B6b-9
Try this:
%28a%2Bb-3%29%28a-b%2B3%29


Average/51584: my son has a problem like this to figure it out what is the missing number
-1, ?, -3 1/2, ?, -6, -7 1/4, ?, ?.
1 solutions

Answer 34401 by Earlsdon(6287) About Me  on 2006-09-10 14:38:19 (Show Source):
You can put this solution on YOUR website!
Provide the missing numbers:
-1, ?, -3 1/2, ?, -6, -7 1/4, ?, ?,
First, you'll notice that the numbers are getting smaller (more negative) so it is possible that subtraction involved.
You can test this on the two adjacent numbers in the set...-6, and -7 1/4
You can see that if you subtract -7 1/4 from -6 you'll get a difference of
1 1/4.
So, if you subtract 1 1/4 from the first number (-1) you'll get -2 1/4
Now subtract 1 1/4 from -2 1/4 and you'll get -3 1/2...so it seem to work with a common difference of 1 1/4
The missing numbers are:
-2 1/4, -4 3/4, -8 1/2, -9 3/4.


Coordinate-system/51583: I have the following problem; Write the equation of the line which passes through the point (2,1) and is parallel to the equation y = 5/2x + 6. My answer is y= 5/2x - 1 is this correct? Please help.
1 solutions

Answer 34399 by Earlsdon(6287) About Me  on 2006-09-10 14:23:54 (Show Source):
You can put this solution on YOUR website!
Sorry, but no cigar!
You do have the first term corect (%285%2F2%29x but the y-intercept (b) is not right.
Let's start with what you have done.
y+=+%285%2F2%29x+%2B+b To find the value of b, you need to substitute the x- and y-coordinates of the given point (2, 1)
1+=+%285%2F2%29%282%29+%2B+b Simplify this.
1+=+5+%2B+b Subtract 5 from both sides of the equation.
-4+=+b Now you can write the equation:
y+=+%285%2F2%29x+-+4
Here are the two lines on a graph:
y+=+%285%2F2%29x%2B6 Red line.
y+=+%285%2F2%29x-4 Green line.
graph%28300%2C200%2C-5%2C5%2C-5%2C8%2C%285%2F2%29x%2B6%2C%285%2F2%29x-4%29


Radicals/51398: This question is from textbook Amsco's Mathematics B
The question requires that the problem be written in it's simplest form.
I need to check if my answer is correct.
6 square root 4/3
1 solutions

Answer 34337 by Earlsdon(6287) About Me  on 2006-09-09 22:04:24 (Show Source):
You can put this solution on YOUR website!
Simplify:
6sqrt%284%2F3%29 Rewrite this as:
6sqrt%284%281%2F3%29%29 Now you can take the square root of 4 (that's 2) and put it outside the radical.
6%2A2sqrt%281%2F3%29 Simplifying this, you get:
12sqrt%281%2F3%29


Coordinate-system/51380: Please help me solve the following problem; Write the eqation of the line that passes through the point?(2,1) and is parallel to the line with the eqation y=5/2x + 6. I honestly do not know where to even begin on this.
1 solutions

Answer 34336 by Earlsdon(6287) About Me  on 2006-09-09 22:00:16 (Show Source):
You can put this solution on YOUR website!
Let's write the required equation of the line in the "slope-intercept" form: y+=+mx%2Bb Where: m is the slope of the line and b is the y-intercept of the line.
Remember that parallel lines have the same slope.
So, your new line is parallel the the line whose equation is:
y+=+%285%2F2%29x%2B6 Comparing this with the slope-intercept form:
y+=+mx%2Bb you can see that the slope of this line is m+=+5%2F2 and, because the new line is parallel to this, it too will have a slope of m+=+5%2F2.
So, step 1, for the new line, you can write:
y+=+%285%2F2%29x+%2B+b Now all you need to do is to find the value of b, the y-intercept of the new line.
You can do this by substituting the x- and y-coordinates of the given point (2, 1) into the equation y+=+%285%2F2%29x+%2B+b and solve for b.
1+=+%285%2F2%29%282%29+%2B+b Simplify this.
1+=+5+%2B+b Subtract 5 from both sides of the equation.
-4+=+b You can write the final equation now that you have the slope m+=+5%2F2 and the y-intercept b+=+-4:
y+=+%285%2F2%29x+-+4 ...and that's it!


Equations/51395: how do you do this problem? 1/a + 2/b = 3/c Solve for b. I have tired my brain out trying to solve this problem!! Thanks!!
1 solutions

Answer 34334 by Earlsdon(6287) About Me  on 2006-09-09 21:45:01 (Show Source):
You can put this solution on YOUR website!
Ok. give your brain a rest and let's see what can be done with this:
Solve:
1%2Fa+%2B+2%2Fb+=+3%2Fc for b. First, subtract 1%2Fa from both sides.
2%2Fb+=+3%2Fc+-+1%2Fa Now combine the two fractions on right side.
2%2Fb+=+%283a-c%29%2Fac Next, multiply both sides by ac
2ac%2Fb+=+3a-c Then multiply both sides by b
2ac+=+b%283a-c%29 Finally, divide both sides by (3a-c)
2ac%2F%283a-c%29+=+b
So, b+=+2ac%2F%283a-c%29


Rate-of-work-word-problems/51327: This question is from textbook college algebra
Please help...got stuck on this problem for long time...thank you!!
"Fencing Dog Pens" Clint is constructing 2 adjacent rectangular dog pens. Each pen will be three times as it is wide, and the pens will share a common long side. If Clint has 65ft of fencing, what are the dimensions of each pen??
1 solutions

Answer 34274 by Earlsdon(6287) About Me  on 2006-09-09 12:36:52 (Show Source):
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I assume that you meant to write..."Each pen will be three times as long as it is wide,..."
If we let the width be W, then the length of each pen will be: L = 3W.
From the problem description, the two adjacent pens will have three long sides and four short sides.
Each long side will be 3W in length and there are three of these,
so we have 3(3W) = 9W. This is the total of the lengths.
The short sides (Widths) wll each be W in length and there are four of these, so we have 4(W) = 4W This the total of the widths.
Adding up all of these, we get:
9W + 4W = 13W and this is equal to the total length of the fence (perimeter) of 65 feet.
13W = 65 Divide both sides by 13.
W = 5 feet.
This is the length of each width, but there are four of these, so we have the total for the widths is: 4(5) = 20 feet.
The length, L = 3W = 3(5) = 15 feet
The three lengths is then: 3(15) = 45 feet.
Each pen measures: (L X W) = 15 ft. by 5 ft.
Check:
Adding up the the total widths and the total lengths, we get: 20 ft + 45 ft = 65 ft.



Linear_Equations_And_Systems_Word_Problems/51329: Michael rented a truck for one day. There was a rental fee of $20.99, and there also was a charge of 25 cents for each mile. Michael paid $95.74 when he returned the truck. For how many miles did he drive the truck?

1 solutions

Answer 34270 by Earlsdon(6287) About Me  on 2006-09-09 12:14:32 (Show Source):
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Michael paid a total of $95.74 when he returned the truck. So, if we first deduct (subtract) the rental fee of $20.99 to see what he actually paid for mileage. Then we can divide the remainder by $0.25 to see how many miles he drove.
(Total cost - rental fee)/$0.25 = number of miles driven.
($95.74 - $20.99}/$0.25 = ($74.75)/$0.25 = 299
So Michael paid for 299 miles


sets-and-operations/51320: Find values for m and b in the following system so that the solution to te system is ( -3, 4).
5x + 7y = b
mx + y = 22
1 solutions

Answer 34261 by Earlsdon(6287) About Me  on 2006-09-09 10:45:05 (Show Source):
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Find the values of m and b given the solution to the system is (-3, 4):
5x + 7y = b
mx +y = 22
Substitute the x- and y-coordinates from the given point (-3, 4) into each equation and solve for the b and m.
5(-3) + 7(4) = b Simplify.
-15 + 28 = b
b = 13
mx + y = 22
m(-3) + 4 = 22 Subtract 4 from both sides of the equation.
-3m = 18 Divide both sides by -3.
m = -6
You can verify these solutions by substituting b = 13 and m = -6 into the appropriate equation and doing the math.
Try this yourself.


Radicals/51295: This question is from textbook
I worked this out sqrt(3x+3)- 9 = 0; I came up with x=2 and checking the problem by plugging 2 in, I came up with 81 not = to 9. Can someone advise please?
1 solutions

Answer 34229 by Earlsdon(6287) About Me  on 2006-09-08 23:31:19 (Show Source):
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Solve:
sqrt%283x%2B3%29-9+=+0 Add 9 to both sides of the equation.
sqrt%283x%2B3%29+=+9 Square both sides.
3x%2B3+=+81 Subtract 3 from both sides.
3x+=+78 Divide both sides by 3.
x+=+26 Check:
sqrt%283%2826%29%2B3%29-9+=+0
sqrt%2878%2B3%29-9+=+0
sqrt%2881%29-9+=+0
9-9+=+0
0+=+0


Linear-systems/51170: how does the graphfor the following equations look? y=x-1/2 and y=3x+1
1 solutions

Answer 34202 by Earlsdon(6287) About Me  on 2006-09-08 18:06:15 (Show Source):
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Graph:
y+=+x-1%2F2 The red line.
y+=+3x%2B1 The green line.
graph%28300%2C200%2C-5%2C5%2C-5%2C5%2Cx-%281%2F2%29%2C3x%2B1%29


Volume/51174: Harriet's family just purchased an above ground circular swimming pool. The diameter of the pool is 12 feet. The depth of the pool is 4 feet. How much water is needed to completely fill the pool? Use the formula V=(pie)r(squared)h. Let (pie)=3.14
1 solutions

Answer 34201 by Earlsdon(6287) About Me  on 2006-09-08 18:01:43 (Show Source):
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The first step, of course, is to find the volume of the circular (really cylindrical) swimming pool.
V+=+%28pi%29r%5E2h Where: r (radius) is 6 ft. and h (depth) is 4 ft. Making these substitutions:
V+=+3.14%286%5E2%29%284%29
V+=+3.14%2836%29%284%29
V+=+452.16 cubic feet.
The next step is to discover how many cubic feet are occupied by 1 U.S. gallon of water.
1 U.S. gallon = 0.1336816 cubic feet.
So, how many of these will fit into 452.16 cubic feet? This sounds like a division problem, so we'll divide 452.16 cubic feet by 0.0336816 cubic feet /gallon.
452.16%2F0.1336816+=+3382.365Gallons (Aproximately)


Quadratic_Equations/51271: I am confused on how to solve this problem.
Suppose a baseball is shot up from the ground straight up with an initial velocity of 32 feet per second. A function can be created by expressing distance above the ground, s, as a function of time, t. This function is s = -16t2 + v0t + s0
• 16 represents 1/2g, the gravitational pull due to gravity (measured in feet per second2).
• v0 is the initial velocity (how hard do you throw the object, measured in feet per second).
• s0 is the initial distance above ground (in feet). If you are standing on the ground, then s0 = 0.
What is the maximum height of the ball? What time will the maximum height be attained?
I wasn't sure how to do this. I want to say 32 feet. But I'm not sure.
1 solutions

Answer 34197 by Earlsdon(6287) About Me  on 2006-09-08 17:25:24 (Show Source):
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Let's answer all three questions for the problem here.
Since the initial upward velocity is given as 32 ft/sec, you can write the function of height,s, as a function of time, t. If you were to graph this function, you would get a parabola that opens downward. We know that because the coefficient of the t^2 term is negative.
s%28t%29+=+-16t%5E2+%2B+32t For question #2, the time at which maximum height is attained by the baseball can be found by locating the vertex of the parabola then finding the value of t that corresponds to this location.
The t-coordinate of the vertex is given by: t+=+-b%2F2a.
Where do the a and b come from?
They come from comparing your equation with the general standard form of the quadratic equation: ax%5E2+%2B+bx+%2B+c+=+0 but in your equation of course, the independent variable is t rather than x and a = -16 and b = 32.
So, let's find the the value of t at which the vertex is located.
t+=+-b%2F2a In your equation, a = -16 and b = 32. Substituting these values into the appropriate places, we get:
t+=+%28-32%29%2F2%28-16%29 Simplifying this:
t+=+1second.
The baseball attains its maximum height in 1 second.
For question #1, the maximum height attained by the baseball can be found by substituting t = 1 in the original function for the height: s%28t%29+=+-16t%5E2%2B32t and solveing for the height, s.
s%281%29+=+-16%281%29%5E2+%2B+32%281%29 Simplifying, we get:
s%281%29+=+-16%2B32
s%281%29+=+16feet.
The maximum height attained by the baseball is 16 feet.
Question #3 (Posted separately) At what time does the baseball return to the ground? Well, that's really asking at what time is the height of the base = 0 feet. There will, of course, be two anwers to this question. The height will be zero at the start of the action and then it will be zero when the baseball returns to earth, so only the second solution is of interest to us. To find this time, we'll set the function for the height equal to zero and solve for the time, t.
-16t%5E2%2B32t+=+0 Factor a t.
t%28-16t%2B32%29+=+0 Apply the zero product principle.
t+=+0 and/or -16t%2B32+=+0
Well, t = 0 is the first solution whch we can ignore.
-16t+%2B+32+=+0 Subtract 32 from both sides of the equation.
-16t+=+-32 Divide both sides by -16.
t+=+2 seconds.
The baseball returns to the ground at 2 seconds.


Triangles/51273: isbn 0618372628
Find the perimeter of a right triangle with legs that measure 5cm and 9cm.
1 solutions

Answer 34196 by Earlsdon(6287) About Me  on 2006-09-08 16:46:25 (Show Source):
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Since you are given the lengths of only the two legs, you need to find the length of the hypotenuse of this right triangle before you can find the perimeter. Use the Pythagorean theorem to find the length of the hypotenuse, c.
c%5E2+=+a%5E2%2Bb%5E2
c+=+sqrt%28a%5E2%2Bb%5E2%29 Substitute a = 5 and b = 9
c+=+sqrt%285%5E2%2B9%5E2%29
c+=+sqrt%2825%2B81%29
c+=+sqrt%28106%29
c+=+10.3cm. (Approximately} The perimeter is:
P+=+a%2Bb%2Bc
P+=+5%2B9%2B10.3
P+=+24.3cm (Approximately)


Polynomials-and-rational-expressions/51274: This question is from textbook
I am drawing a blank on this; do I multiply or add the denominators?
(x-1/3)*(x+1/3)
1 solutions

Answer 34195 by Earlsdon(6287) About Me  on 2006-09-08 16:36:37 (Show Source):
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Multiply:
%28x-1%2F3%29%2A%28x%2B1%2F3%29 Use FOIL to multiply these two factors.
%28x-1%2F3%29%28x%2B1%2F3%29+=+x%5E2+%2B%281%2F3%29x+-+%281%2F3%29x+-+%281%2F3%29%5E2 Simplify this.
x%5E2-1%2F9


Linear-equations/51250: Driving down a mountain, Tom finds that he has descended 1800 ft in elevation by the time he is 3.25 mi horizontally away from the top of the mountain. Find the slope of his descent to the nearest hundredth.
I thought that the first step would be to create an equation
y= 3.25x + 1800
But I need to find the slope, which requires 2 points (y2-y1 over x2-x1).
I am not sure what formula I shoudl start with to arrive at the slope, as requested.

1 solutions

Answer 34180 by Earlsdon(6287) About Me  on 2006-09-08 10:47:29 (Show Source):
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I know this is algebra and it seems like everything in algebra requires an equation of some sort. But sometimes, a little common sense will get the job done with a lot less confusion.
Try this.
The definition of slope is "rise over run".
In your problem, you could say Tom "rose" (in reverse) 1800 feet while he "ran" (horizontally) 3.25 miles.
So the slope here is Rise/Run = 1800 ft./3.25 miles.
But you'll need to change the units so that they are the same, either all in feet or all in miles. All in feet seems to be the better approach, so how many feet are there in 3.25 miles?
Well, 1 mile = 5280 ft. Multiply both sides by 3.25
3.25 mies = 3.25(5280) ft.
3.25 miles = 17160 ft. Now we can calculate the slope:
1800%2F17160+=+0.104895 But you need to round to the nearest hundreth.
The slope is 0.10


Linear-equations/51248: Please help: Determine the equation of the line that has a slope of 4 and passes through the point (2,8). Write the equation in slope intercept form
1 solutions

Answer 34179 by Earlsdon(6287) About Me  on 2006-09-08 10:32:37 (Show Source):
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Write the equation in slope-intercept form:
y+=+mx%2Bb
You are given the slope, m = 4, so you can write:
y+=+4x%2Bb Now you need to find the value of b, the y-intercept. This is easily done because you were also given a point (2, 8) through which the line passes.
So you substitute the (x, y) of the given popint (2, 8) into the equation y+=+4x%2Bb and solve for b.
8+=+4%282%29+%2B+b Simplify.
8+=+8+%2B+b Subtract 8 from both sides of the equation.
0+=+b So b = 0. Now you can write the final equation of the line whose slope is 4 and which passes through the point (2, 8).
y+=+4x
Just out of curiosity, let's see what that looks like on a graph:
graph%28300%2C200%2C-5%2C5%2C-5%2C10%2C4x%29


Trigonometry-basics/51136: This question is from textbook Alegra 2 and Incremental Development
The volume of a circular cylinder is 250pi cm cube. What is the height of the cylinder?
Radius is 5

1 solutions

Answer 34107 by Earlsdon(6287) About Me  on 2006-09-07 18:28:57 (Show Source):
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The volume of a right circular cylinder is given by:
V+=+%28pi%29r%5E2h Let's first solve this for the height, h, by dividing both sides by %28pi%29r%5E2.
h+=+V%2F%28pi%29r%5E2 Now you can substitute V+=+250%28pi%29, and r+=+5
h+=+250%28pi%29%2F%28pi%29%285%5E2%29 You can cancel the %28pi%29 and 5%5E2+=+25
h+=+250%2F25 Simplify.
h+=+10 cm.


Trigonometry-basics/51134: ok i dont know what categorey it goes in.. but i need help on changing trinomials into binomials.
I am a visual learner so please show me how to convert them.
1 solutions

Answer 34106 by Earlsdon(6287) About Me  on 2006-09-07 18:19:50 (Show Source):
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It seems to me that you are into "factoring" trinomials, which is basically a process of converting trinomials into binomial factors. Of course, not all trinomials can be factored, but "factoring trinomials" constitutes an entire lesson for those that can be factored.
Here's an elementary example:
Factor the following expression:
x%5E2%2B3x%2B2
The factors will be two "binomials" of the following form:
%28x%2Ba%29%28x%2Bb%29 You'll need to find the values of a and b. These two binomial factors, when multiplied together will result in the original trinomial expression.
Comparing the binomial factors with the trinomial, you can write this:
x%5E2%2B3x%2B2+=+x%5E2+%2B+%28a%2Bb%29x+%2B%28a%2Ab%29 so this means that:
a+b = 3 and a*b = 2
What are the possibilities?
a = 1 and b = 2 or
a = 2 and b = 1
Let's try these in the binomial forms and see what we get.
x%2B1%29%28x%2B2%29 Multiply these factors using the FOIL method.
%28x%2B1%29%28x%2B2%29+=+x%5E2%2B2x%2Bx%2B2 Simplifying this, we get:
x%5E2%2B3x%2B2 The original trinomial!

You would get exactly the same result if you used:
a = 2 and b = 1


Linear-equations/51131: Aqueducts were once used to carry water from rivers using gravity. Water flowing too quickly might damage an aqueduct, but water flowing too slowly might not keep the aquiducts clear. One of the best and most common designs for an aqueduct was to raise it 3 meters for every kilometer in length. What is the slope of an aqueduct built with this design?
I need help in understanding how to find the slope from this word problem because I don't understand anything about word problems. So if you could please help me to solve this problem step by step it would be helpful.



1 solutions

Answer 34101 by Earlsdon(6287) About Me  on 2006-09-07 18:00:27 (Show Source):
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Remember the basic definition of slope..."Rise over Run"
In your problem, the aqueduct rises 3 meters (Rise = 3) for every kilometer (1,000 meters) in length (Run = 1,000 meters).
So the slope is Rise/Run = 3/1000 = 0.003
Does this help?


Expressions-with-variables/51130: This question is from textbook Algebra I
please help me with this problem

the product of $25 and the number "M" of club memberships is greater than or equal to $500
1 solutions

Answer 34099 by Earlsdon(6287) About Me  on 2006-09-07 17:54:26 (Show Source):
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Presumably you want to solve for M?
%2425%28M%29+%3E=+%24500 Divide both sides of the inequality by 25.
M+%3E=+20


Geometry_proofs/51105: Hello!
Here's my question:
In triangle KLM, P is the midpoint of the line segment LM.
Prove that if PL = PK = PM, angle LKM = 90 degrees.
I have been struggling on this question for quite some time now. All I found out from the web is to introduce a point O so that KPO is a line segment with P at the midpoint, and then show that KLOM is a rectangle.
Please Help! Thank You!
1 solutions

Answer 34096 by Earlsdon(6287) About Me  on 2006-09-07 17:48:15 (Show Source):
You can put this solution on YOUR website!
I'm not certain that the following constitutes a "proof" in the formal sense of the word, but it certainly provides a demonstration.
If you accept the principle that "An angle inscribed in a semi-circle is a right angle", then read the following:
The line segment LM is the diameter of a circle.
The mid-point of LM is therefore the center of this circle and PL and PM are both radii of this circle and they, of course, are equal.
Point K is a point on the circumference of the circle, not coincident with either L or M.
The segment PK is also a radius of the circle, so that:
PL = PK = PM
Segments KL and KM form the other two sides of a triangle.
The angle LKM is inscribed in a semi-circle and is, therefore, a right angle. A right angle = 90 degrees.



Expressions-with-variables/51107: a and b is unknown
express x in terms of a and b.
ax-5.6=bx+12.1
1 solutions

Answer 34087 by Earlsdon(6287) About Me  on 2006-09-07 17:14:54 (Show Source):
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Express x in terms of a and b.
ax-5.6+=+bx%2B12.1 Add 5.6 to both sides of the equation.
ax+=+bx%2B17.7 Now subtract bx from both sides.
ax-bx+=+17.7 Factor out the x.
x%28a-b%29+=+17.7 Finally, divide both sides by (a-b)
x+=+17.7%2F%28a-b%29


Equations/51108: Find the two solutions to this equation.
ax^2+8ax=0
1 solutions

Answer 34085 by Earlsdon(6287) About Me  on 2006-09-07 17:08:29 (Show Source):
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Find the two solutins:
ax%5E2%2B8ax+=+0 First, factor out an x.
x%28ax%2B8a%29+=+0 Apply the zero product principle.
x = 0 and/or ax+8a = 0
x = 0 is one of the two solutions.
ax%2B8a+=+0 Subtract 8a from both sides.
ax+=+-8a Divide both sides by a.
x+=+-8
x = -8 is the other solution.


absolute-value/51086: This question is from textbook
solve the following equations for y:
5x-y=10
x+4y=-8
0.1x+o.5y=3.5
2x=3y+9
5x-6y+12=0
x-2xy=1
I do not understand how i am suppost to solve for y? can you please explain how to solve for y in these problems?
1 solutions

Answer 34064 by Earlsdon(6287) About Me  on 2006-09-07 11:36:24 (Show Source):
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Solving for y simply means that you must get the y on one side of the equals sign by itself using the standard rules of algebra.
1) 5x-y = 10 Here, you would first add y to both sides of the equation.
5x = 10+y Then you subtract 10 from both sides.
5x-10 = y Many teachers like to see the dependent variable (y in this case) on the left side, so rewrite this as:
y = 5x-10...and there you have it.
2) x+4y = -8 In this one, you would subtract x from both sides.
4y = -x-8 then you divide both sides by 4.
y = -(1/4)x - 2
Do you see the idea here? You want to rewrite each equation so that it's in the form...y = something. Let's do one more:
0.1x + 0.5y = 3.5 Here, you need to get rid of the decimals in a way that leaves you with integral (whole number) numbers of y. You can do this by multiplying everything by 2.
(2)0.1x + (2)0.5y = (2)3.5 Simplify this.
0.2x + y = 7 Now subtract 0.2x from both sides.
y = -0.2x + 7
Ok now try the others on your own.
If you are still having trouble with it, repost.


Linear_Equations_And_Systems_Word_Problems/51074: This question is from textbook Applied College Algebra
The height, in feet, of a rock,above the Colorado River that is thrown from the north rim of the Grand Canyon is given by Height = 5700 - 16t^2, where t is the number of seconds after the rock above the river 5 seconds after it is released.
1 solutions

Answer 34058 by Earlsdon(6287) About Me  on 2006-09-07 11:02:02 (Show Source):
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It seems as though you might have missed part of the problem statement.
Do you have to find the height of the rock 5 seconds after it is dropped from the North Rim at a height of 5700 feet? Using the given function:
h%28t%29+=+-16t%5E2%2B5700 Substitute t = 5 and solve for h.
h%285%29+=+-16%285%5E2%29%2B5700
h%285%29+=+-400%2B5700
h%285%29+=+5300feet.
The height of the rock would be 5300 feet five seconds after it was dropped from a height of 5700 feet.


Radicals/51085: I have been away from school the past few days because i was sick, and i am really not understanding these questions. i am also not sure if this is the right section to be asking this question in, but nothing else seemed to fit
(x^2-64)/(5x) * (10x^2)/(x+8)
1. what i thought to do is factor the denomanator so it would be (x+8)(x-8)/(5x) * (10x^2)/(x+8) then the two x + 8's cancel out....once u have the final answer as (x-8)/(5x) * (10x^2)/1---do u just multiply?? and how do u multiply??
1 solutions

Answer 34055 by Earlsdon(6287) About Me  on 2006-09-07 10:50:23 (Show Source):
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Well, it looks like you haven't lost your touch.
Your initial step was quite correct. I am assuming that the task is to simplify the given expression.
%28%28x%5E2-64%29%2F%285x%29%29%28%2810x%5E2%29%2F%28x%2B8%29%29 You correctly factored the numerator of the first fraction.
%28%28%28x%2B8%29%28x-8%29%29%2F%285x%29%29%28%2810x%5E2%29%2F%28x%2B8%29%29 and you also correctly cancelled the (x+8)'s
%28%28x-8%29%2F%285x%29%29%28%2810x%5E2%29%2F1%29 At this point, you can cancel 5x's in the denominator and from the 10x%5E2 in the numerator.
%288-x%29%282x%29 Finally, you can multiply these two factors.
16x-2x%5E2


Expressions-with-variables/50986: I need the method for solving this more than the answer, but both would be appreciated:
Mark launched a model rocket using an engine which will generate a speed of 180 feet per second. The formula h = rt - 16t squared gives the height of an object projected upward at a rate of r feet per second after t seconds. After how many seconds will Mark's rocket reach a height of 464 feet? After how many seconds will it be at that height again? Thank you.
1 solutions

Answer 34031 by Earlsdon(6287) About Me  on 2006-09-06 22:08:54 (Show Source):
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Step 1.
Rewrite your equation in the form of a quadratic function.
h%28t%29+=+-16t%5E2+%2B+rt This is function for the height, h, of an object propelled upwards as a function of time, t. Here, r is given as 180 ft/sec. This fits the situation of Mark's rocket. You are being asked to find at what time, t, will the height, h, be 464 feet. Because your equation is quadratic, you can expect to get two solutions.
Step 2. Set h(t) = 464 in the quadratic equation above and solve for t.
464+=+-16t%5E2%2B180t Put this into standard form by subtracting 464 from both sides.
-16t%5E2%2B180t-464+=+0
Step 3. Solve the quadratic equation for t by the most convenient method. You can simplify this equation a bit by dividing through by -4 to get:
4t%5E2-45t%2B116+=+0 Now you can factor this.
%28t-4%29%284t-29%29+=+0 Apply the zero product principle:
t-4+=+0 and/or 4t-29+=+0
If t-4+=+0 then t = 4
If 4t-29+=+0 then t+=+29%2F4 or t+=+7.25
The two solution are:
The height of the rocket will reach 464 feet in 4 seconds, ascending.
The height of the rocket will be at 464 feet again in 7.25 seconds descending.


Expressions-with-variables/51055: I dont understand how to solve problems such as this....
5x-16=3x
1 solutions

Answer 34026 by Earlsdon(6287) About Me  on 2006-09-06 21:33:21 (Show Source):
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Solve for x:
5x-16+=+3x The idea is to get the x onto one side of the equals sign. Start by subtracting 3x fom both sides of the equation.
2x-16+=+0 Now add 16 to both sides.
2x+=+16 Finally, divide both sides by 2.
x+=+8
Check: Set x = 8 in the original equation.
5%288%29-16+=+3%288%29 Simplify.
40-16+=+24
24+=+24 It checks!


Expressions-with-variables/51054: two fifths the cube of a number
what is the algebraic expression
1 solutions

Answer 34024 by Earlsdon(6287) About Me  on 2006-09-06 21:28:53 (Show Source):
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If n is the number, it would look like:
%282%2F5%29n%5E3


Rational-functions/51049: Please help me write the perimeter P of a square as a function of the area.
1 solutions

Answer 34022 by Earlsdon(6287) About Me  on 2006-09-06 21:26:54 (Show Source):
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Let the sides of the square = s
The perimeter would be:
P+=+4s
The area of the square would be:
A+=+s%5E2 Take the square root of both sides.
sqrt%28A%29+=+s Subsitute this s into the equation for the perimeter.
P+=+4sqrt%28A%29