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Triangles/93150: This question is from textbook
Problem:
One leg of a right triangle has a length of 3m. The other sides have lengths that are consecutive integers. Find these lenths.
The other leg is ____ m
The length of the hypotenuses is ____m

I get the consecutive inegers n, n+1
and if I use the formula a^2 + b^2 = c^2 - I don't know what
to plug in for c. I've been shown several ways, and now
I'm just confused.
Thanks!!!



1 solutions

Answer 67784 by Earlsdon(6294) About Me  on 2007-08-17 18:36:00 (Show Source):
You can put this solution on YOUR website!
Well, on this problem you do have to make at least one assumption:
The given side of 3 meters is (or is not) the hypotenuse.
If you assume that it is the hypotenuse, it is therefore the longest of the three sides of the right triangle.
Since the other two sides are consective integers and each is less then 3, they can only be 1 and 2 mters in length.
Well, as soon as you apply the Pythagorean theorem, you soon see that this cannot be so, because 3%5E2 does not equal 1%5E2+%2B+2%5E2.
So the 3-meter side is one of the legs, right?
Now you have a choice: Is it the shorter leg or the longer leg (not the hypotenuse)?
Let's try the shorter leg.
So the hypotenuse, being the longest side must be n+1 and the other leg must be n. Applying the Pythagorean theorem: c%5E2+=+a%5E2%2Bb%5E2
%28n%2B1%29%5E2+=+n%5E2+%2B+3%5E2
n%5E2%2B2n%2B1+=+n%5E2+%2B+9 Subtract n%5E2 from both sides.
2n%2B1+=+9
2n+=+8
n+=+4 and...
n%2B1+=+5
So, the hypotenuse is 5 meters,and the other leg is 4 meters.
If you were familiar with Pythagorean triplets, you could easily have guessed this result.



Quadratic_Equations/93122: I need help with these problems
Solve by using the quadratic formula: 3x^2=11x+4


and also find the axis of symmetry: y=-x^2+4x+2


Thanks a million
1 solutions

Answer 67773 by Earlsdon(6294) About Me  on 2007-08-17 15:10:09 (Show Source):
You can put this solution on YOUR website!
1) Solve using the quadratic formula:x+=+%28-b%2B-sqrt%28b%5E2-4ac%29%29%2F2a
3x%5E2+=+11x%2B4
First, write the equation in standard form for quadratic equations:
ax%5E2%2Bbx%2Bc+=+0
3x%5E2-11x-4+=+0 Here, you can see that: a = 3, b = -11, and c = -4
Make the appropriate substitutions into the formula and solve for x:
x+=+%28-%28-11%29%2B-sqrt%28%28-11%29%5E2-4%283%29%28-4%29%29%29%2F2%283%29 Simplify this.
x+=+%2811%2B-sqrt%28121-%28-48%29%29%29%2F6
x+=+%2811%2B-sqrt%28169%29%29%2F6
x+=+%2811%2B13%29%2F6 or x+=+%2811-13%29%2F6
x+=+24%2F6 or x+=+-2%2F6
x+=+4 or x+=+-1%2F3
2) Find the axis of symmetry for:
y+=+-x%5E2%2B4x%2B2
The axis of symmetry is given by:
x+=+%28-b%29%2F4a
Your equation here is already in standard form:y+=+ax%5E2%2Bbx%2Bc so a = -1, b = 4, and c = 2
The axis of symmetry is:
x+=+%28-4%29%2F2%28-1%29
x+=+%28-4%29%2F%28-2%29
x+=+2 This is the equation of axis of symmetry!


Graphs/93124: Use a graphing utility to approximate (to two decimals) any relative minimum or maximum values of the function.

f(x) =2x^3+3x^2-12X
1 solutions

Answer 67770 by Earlsdon(6294) About Me  on 2007-08-17 14:48:52 (Show Source):
You can put this solution on YOUR website!
Find the relative maximum/minimum, by graphing, of:
f%28x%29+=+2x%5E3%2B3x%5E2-12x
graph%28600%2C400%2C-5%2C5%2C-10%2C20%2C2x%5E3%2B3x%5E2-12x%29
From the graph, it looks like you have a relative maximum at x = -2 and a relative minimum at x = 1.


Linear-equations/92938: In the x,y plane, what is perpendicular to the graph of the linear equation 3x-4y=0
I've done this over and over but i can't figure it out. The answer is supposed to be y=-(4/3)x+12 but i keep getting y=(3/4)x+0. Thank you for your help!
1 solutions

Answer 67633 by Earlsdon(6294) About Me  on 2007-08-16 11:39:23 (Show Source):
You can put this solution on YOUR website!
What is perpendicular to the graph of:
3x-4y+=+0
You'll recall that if lines are perpendicular, then their slopes are the negative reciprocal of each other. So putting your equation into the slope-intercept form (y = mx+b) where we can readily identify the slope, m:
y+=+%283%2F4%29x ...and you can see that the slope, m+=+3%2F4 and you'll also notice that the y-intercept, b, is zero (This line passes through the origin)
Now that you have you slope, the slope of any line that is perpendicular to this one will be the negative reciprocal of 3/4 or -4/3, so you can write:
y+=+%28-4%2F3%29x+%2B+b
Notice that this equation is for a whole set of lines having the same slope, not just one line, and without additional information, such as the y-intercept, you really cannot identify a specific line, can you?
So the given answer y+=+%28-4%2F3%29x+%2B+12 certainly will be a correct answer, but so will your answer y+=+%28-4%2F3%29x%2B0(Green line)
The graph below should illustrate this quite clearly:(The graph of the given equation is in red)



Quadratic_Equations/92925: I am having problems with this word problem.

The demand and supp;y equations for a certain item are given by
D=-5p+40
S=-p^2+30-8
find the equilibrium price.
Thanks a million
1 solutions

Answer 67630 by Earlsdon(6294) About Me  on 2007-08-16 11:18:59 (Show Source):
You can put this solution on YOUR website!
Find the equilibrium price, p, for the Demand and Supply equations:
D+=+-5p%2B40
S+=+-p%5E2%2B30p-8 I assume that you had a typo in your post because you had written:S+=+-p%5E2%2B30-8
The equilibrium occurs when demand, D, equals supply, S.
-5p%2B40+=+-p%5E2%2B30p-8 Let's put this into a standard-form quadratic equation:
ax%5E2%2Bbx%2Bc+=+0.
p%5E2-35p%2B48+=+0 Solve using the quadratic formula:p+=+%28-b%2B-sqrt%28b%5E2-4ac%29%29%2F2a
p+=+%28-%28-35%29%2B-sqrt%28%28-35%29%5E2-4%281%29%2848%29%29%29%2F2%281%29
p+=+%2835%2B-sqrt%281225-192%29%29%2F2
p+=+%2835%2B-sqrt%281033%29%29%2F2
p+=+%2835%2B32.14%29%2F2 or p+=+%2835-32.14%29%2F2
The final answer is that there are two equilibrium prices:
p = $33.57 or p = $1.43


test/92937: The median of a set of 9 consecutive integers is 42. What is the greatest of these 9 integers?
1 solutions

Answer 67629 by Earlsdon(6294) About Me  on 2007-08-16 10:53:16 (Show Source):
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Since the "median" of a set of numbers is the middle number and the given set cosists of consecutive integers, then you know that 42 is the middle integer of these nine consecutive integers, so the set looks like...
38,39,40, 41,42,43,44,45,46
The greateset integer is 46


Trigonometry-basics/92930: This question is from textbook Algebra and Trigonometry
find the vertical asymptote of the rational function: f(x)=3x-12/4x-2
1 solutions

Answer 67627 by Earlsdon(6294) About Me  on 2007-08-16 10:46:50 (Show Source):
You can put this solution on YOUR website!
Find the vertical asymptote of:
f%28x%29+=+%283x-12%29%2F%284x-2%29
Notice that, in this function, the denominator will be zero when x = 1/2
4x-2+=+0
4x+=+2
x+=+2%2F4
x+=+1%2F2
The graph of this function has a "discontinuity" at x = 1/2, the line, x = 1/2 is a vertical asymptote.
graph%28600%2C400%2C-5%2C5%2C-5%2C5%2C%283x-12%29%2F%284x-2%29%29


Linear_Algebra/92935: This question is from textbook
f(x) = 3x(2x – 1). f(–1) =
1 solutions

Answer 67622 by Earlsdon(6294) About Me  on 2007-08-16 10:17:54 (Show Source):
You can put this solution on YOUR website!
If f(x) = 3x(2x-1), find f(-1)
To do this, you just substitute -1 into the given function where ever there is an x.
f(-1) = 3(-1)(2(-1)-1) Evaluate the right side.
f(-1) = -3(-2-1)
f(-1) = -3(-3)
f(-1) = 9...and there you have it!


Equations/92827: FIND AN X AND A Y THAT MAKS TIS EXPRESSION TRUE Y=4X-3
1 solutions

Answer 67553 by Earlsdon(6294) About Me  on 2007-08-15 16:45:20 (Show Source):
You can put this solution on YOUR website!
You can find any number of x-y combinations that will work:
y+=+4x-3 Choose x = 5
y+=+4%285%29-3
y+=+20-3
y+=+17
That's just one combination: x = 5 and y = 17
Just choose any value for x, plug it into the equation, solve and you will get the corresponding value of y.


Linear-equations/92823: find the slope of the line passing through the points (-4,0) and (-4,-2).
1 solutions

Answer 67538 by Earlsdon(6294) About Me  on 2007-08-15 16:00:58 (Show Source):
You can put this solution on YOUR website!
Recall that the slope (m) can be described as "Rise over Run" or the change in the y-coordinates over the change in the x-coordinates. In algebrese:
m+=+%28%28y%5B2%5D-y%5B1%5D%29%29%2F%28%28x%5B2%5D-x%5B1%5D%29%29
Of course, the x's and y's are the coordinates of the given points (-4, 0) and (-4, -2) So let's calculate the slope, m, of the line passing through the given points using the formula:
m+=+%28%28-2-0%29%29%2F%28%28-4-%28-4%29%29%29 Simplifying this we get:
m+=+-2%2F0...but, as you know, division by zero is frowned upon in mathematics, so when you see a slope that has zero in the denominator, (a zero run), this is called an "undefined (not a zero) slope".
What it really means is that the line is vertical.


Linear-equations/92817: Adult tickets for a play cost $20 and child tickets cost $16. If there were 27 people at a performance and the theater collected $646 from ticket sales, how many adults and how many children attended the play?
1 solutions

Answer 67535 by Earlsdon(6294) About Me  on 2007-08-15 15:39:16 (Show Source):
You can put this solution on YOUR website!
This problem has no solution!
Why?
Because, if all 27 attendees were adults (at $20 each), the maximum that could be collected for ticket sales would be 27($20) = $540, but the problem states that $646 were collected from ticket sales.
Where did the extra $106 ($646 - $540) come from?


Polynomials-and-rational-expressions/92271: ADD
5b^3 - 8b + 2b^2 and 3b^2 - 7b^3 + 5b
1 solutions

Answer 67132 by Earlsdon(6294) About Me  on 2007-08-11 10:26:22 (Show Source):
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Add:
5b%5E3-8b%2B2b%5E2 and 3b%5E2-7b%5E3%2B5b Group the like-terms together.
%285b%5E3-7b%5E3%29%2B%282b%5E2%2B3b%5E2%29%2B%28-8b%2B5b%29 Combine the like-terms.
-2b%5E3%2B5b%5E2-3b


Polynomials-and-rational-expressions/92273: Simplify each of the following expressions. Write your ansewers with positive exponents only.
(x^2)^-3(x^-2)/ (x^2)^-4
1 solutions

Answer 67130 by Earlsdon(6294) About Me  on 2007-08-11 10:21:37 (Show Source):
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Simplify:
= %28x%5E8%29%2F%28x%5E6%2Ax%5E2%29+=+x%5E8%2Fx%5E8 = 1


Quadratic_Equations/92189: This question is from textbook
If the parabola y - 2 = a(x-3)^2 goes through the point (2,0), what is the
value of a? please HELP!!
1 solutions

Answer 67024 by Earlsdon(6294) About Me  on 2007-08-10 11:55:41 (Show Source):
You can put this solution on YOUR website!
Since you have the equation:
y-2+=+a%28x-3%29%5E2 and a point (2, 0) through which the graph passes, then the given point (2, 0) is said to satisfy the equation y-2+=+a%28x-3%29%5E2.
So you just substitute the x- and y-coordinates of the given point into the equation and solve for a. Substitute x = 2 and y = 0
0-2+=+a%282-3%29%5E2
-2+=+a%28-1%29%5E2
-2+=+a%281%29 So...
a+=+-2 Done!


Rational-functions/92187: This question is from textbook
write each fraction as a terminating or repeating decimal 3/8 huh? i really dont get this
1 solutions

Answer 67022 by Earlsdon(6294) About Me  on 2007-08-10 11:46:22 (Show Source):
You can put this solution on YOUR website!
Convert 3/8 to its decimal equivalent.
Remember, all fractions are division problems...the numerator (top) is divided by the denominator (the bottom)
If you have a calculator, just divide 3 by 8...enter the 3, push the divide key then enter the 8 followed by the = key (or the ENTER key on some calculators).
The diplay window will show .375 (This is a terminating decimal)
Otherwise, you will have to use long division.


real-numbers/92186: This question is from textbook
please help me understand how to write in a common fraction in lowest terms 1.6(the 6 reapeating)

1 solutions

Answer 67021 by Earlsdon(6294) About Me  on 2007-08-10 11:40:12 (Show Source):
You can put this solution on YOUR website!
Write 1.666... as an equivalent fraction in its lowest terms.
Well, the good news is that a repeating decimal (such as 1.666...) is a rational number and can, therefore, be expressed as the ratio of two integers (i.e. a fraction)...but, expressing a repeating decimal as a fraction requires a little more work than does converting a terminating decimal.
Here's how it goes:
First, separate the integer from the decimal so that we can convert just the decimal part (0.666...) to its equaivalent fraction.
Let n = 0.666... Multiply both sides by 10
10n = 6.666... Now subtract n from 10n
10n-n = (6.666...) - (0.666...)
9n = 6 Divide both sides by 9
n = 6/9 ...but n = 0.666..., so
0.666... = 6/9 Reduce this to:
0.666... = 2/3
Finally, add the integer back to get:
1.666... = 1 2/3 or, if you need it as a improper fraction, then:
1.666... = 5/3
You can check this with your calculator by dividing 5 by 3 and the calculator will display 1.666...


Polynomials-and-rational-expressions/92180: Hello I am not sure how to go about this. If the sides of a square are decreased by 3cm, the area is decreased by 81cm^2. What were the dimensions of the original square. I am thinking (x-3)^2=a-81cm^3, but where do I go from here?
1 solutions

Answer 67019 by Earlsdon(6294) About Me  on 2007-08-10 11:24:08 (Show Source):
You can put this solution on YOUR website!
Well, your initial idea is right on!
%28x-3%29%5E2+=+A-81 Where A = original area and x = the original length of the side of the square.
The next step is to recall that A+=+x%5E2, that is; the original area (A) is equal to the original sides squared %28x%5E2%29, so substitute the A with x%5E2 in the first equation then solve for x.
%28x-3%29%5E2+=+x%5E2-81 Expand the left side.
x%5E2-6x%2B9+=+x%5E2-81 Subtract x%5E2 from both sides.
-6x%2B9+=+-81 Subtract 9 from both sides.
-6x+=+-90 Finally, divide both sides by -6.
x+=+15cm.
Check:
%2815-3%292+=+15%5E2-81
12%5E2+=+225-81
144+=+144


Inequalities/91904: Can you please explain how to do this problem. the abosolute value of x-2 is less than or equal to 9. The answer is x is less than or equal to 11 or x is greater than or equal to -7. How do you get these?
1 solutions

Answer 66752 by Earlsdon(6294) About Me  on 2007-08-08 13:25:52 (Show Source):
You can put this solution on YOUR website!
Solve for x:
Recall that if:
|a| <= b then either a <= b or a >= -b
|x-2| <= 9 Remove the absolute-value bars and write two inequalities:
x-2+%3C=+9 or x-2+%3E=+-9 Solve these two inequalities.
x+%3C=11 or x+%3E=-7


Polynomials-and-rational-expressions/91861: This question is from textbook
this problem was a little confuseing i dont know how to sovle this one!! but i do think think answer is either cancels out to 0 or x+y can some one help?
(x-y/x+y)+(x+y/x-y)
1 solutions

Answer 66725 by Earlsdon(6294) About Me  on 2007-08-08 11:04:01 (Show Source):
You can put this solution on YOUR website!
Simplify:
%28%28x-y%29%2F%28x%2By%29%29%2B%28%28x%2By%29%2F%28x-y%29%29 I hope I have this right! Add the two fractions. The LCD is %28x%2By%29%28x-y%29
Do you see how we get this? Now perform the indicated multiplications.
Simplify by combining like-terms.
%282x%5E2%2B2y%5E2%29%2F%28%28x%5E2-y%5E2%29%29 Factor the 2 in the numerator.
2%28%28x%5E2%2By%5E2%29%2F%28x%5E2-y%5E2%29%29...and this is as far as we can go!


Inequalities/91816: Hello,

I need help with this:

If y varies directly as x and y = 25 when x = 10, find y when x = 4.

Thank you
1 solutions

Answer 66661 by Earlsdon(6294) About Me  on 2007-08-07 21:53:09 (Show Source):
You can put this solution on YOUR website!
If y varies directly as x, you can write this as:
y = kx where k is called the constant of proportionality.
To find the value of k, substitute the given values of y (25) and x (10) and solve for k.
25 = 10k Divide both sides by 10.
k = 2.5
Now you have: y = 2.5x so you can find the value of y when x = 4.
y = 2.5(4)
y = 10


Quadratic_Equations/91744: I am having some problems solving these problems
Use the quadratic formula to solve each of the quadratic equations
2x^2-5x=3
and also 3x^2-2x+1=0
Thank you
1 solutions

Answer 66614 by Earlsdon(6294) About Me  on 2007-08-07 13:03:38 (Show Source):
You can put this solution on YOUR website!
Solve for x using the quadratic formula: x+=+%28-b%2B-sqrt%28b%5E2-4ac%29%29%2F2a
Problem 1.
2x%5E2-5x+=+3 Subtract 3 from both sides to get your equation into standard form: ax%5E2%2Bbx%2Bc+=+0
2x%5E2-5x-3+=+0 Apply the formula:
x+=+%28-%28-5%29%2B-sqrt%28%28-5%29%5E2-4%282%29%28-3%29%29%29%2F2%282%29 Now evaluate this.
x+=+%285%2B-sqrt%2825%2B24%29%29%2F4
x+=+%285%2B-sqrt%2849%29%29%2F4
x+=+%285%2F4%29%2B7%2F4
x+=+12%2F4
x+=+3 or
x+=+%285%2F4%29-7%2F4
x+=+-2%2F4
x+=+-1%2F2
You can use the above as a guide to solve problem 2.


Quadratic_Equations/91743: I am having problems with figuring this problem out and need some help
Number problem: Find two consecutive positive integers. Such that the sum of thier squares is 85.
Thank a million

1 solutions

Answer 66602 by Earlsdon(6294) About Me  on 2007-08-07 11:50:39 (Show Source):
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Find two positive consecutive integers such that the sum of their squares = 85.
Let x be the first integer, then x+1 would be the next consecutive integer, so you can write:
x%5E2+%2B+%28x%2B1%29%5E2+=+85 Simplify.
x%5E2%2Bx%5E2%2B2x%2B1+=+85 Subtract 85 from both sides and combine like-terms.
2x%5E2%2B2x-84+=+0 Solve this quadratic equation by factoring.
%282x-12%29%28x%2B7%29+=+0 Apply the zero products principle.
2x-12+=+0 or x%2B7+=+0 so...
2x+=+12
x+=+6 or
x%2B7+=+0 so...
x+=+-7 Discard this solution as you are looking for positive values of x.
The two integers are: 6 and 7
6%5E2%2B7%5E2+=+36%2B49 = 85


Miscellaneous_Word_Problems/91734: Melissa wants to have concrete driveway in front of her house. The driveway will measure 62 1/3 feet long and 19 feet wide; and will be 2/3 foot thick. How many cubic yards of cement will be needed for the driveway? Round your answer to the nearest cubic yard. [1 cubic yd = 27 cubic feet]
I think that you would multiply 62 1/3 by 19 by 2/3 but I am not certain, Please help. I came up with 31 cubic yards.
1 solutions

Answer 66600 by Earlsdon(6294) About Me  on 2007-08-07 11:38:44 (Show Source):
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Well, you have the right idea. You are finding the volume of cement in the driveway and this is done just as you describe. (62 1/3)(19)(2/3) = 789.56 cu.ft.
Now divide this by 27 cu.ft. per cu.yd.
789.56/27 = 29.24 cu.yds. or...
29 cu.yds. rounded to the nearest cu. yd.


Miscellaneous_Word_Problems/91736: Mike invested $6000 for one year. He invested part of it at 9% and the rest at 11%. At the end of the year he earned $624 in interest. How much did he invest at each rate?
1 solutions

Answer 66598 by Earlsdon(6294) About Me  on 2007-08-07 11:28:34 (Show Source):
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Let x = the amount invested at 9%. The interest earned on this amount would then be (0.09)x.
The remainder (6000-x) is invested at 11%. The interest earned on this amount would be (0.11)(6000-x)
The sum (+) of these two amounts is $624.00
You can now write the equation needed to solve for x, the amount invested at 9%.
(0.09)x + (0.11)(6000-x) = $624.00 Simplify and solve for x.
0.09x+660-0.11x = $624.00 Combine like-terms.
(0.09-0.11)x+660 = $624.00 Subtract 660 from both sides.
-0.02x = -$36.00 Divide both sides by -0.02
x = $1800.00 and...
$6000-x = $6000-$1800 = $4200.00
Solution:
$1,800.00 was invested at 9%
$4,200 was invested at 11%
Check:
(0.09)($1,800.00)+(0.11)($4,200.00) = $162.00 + $462.00 = $624.00


Miscellaneous_Word_Problems/91731: Factorise:
#1 a2 + 6ab + 9b2 - 1
PLEASE NOTE THAT IN THE QUESTION a AND b ARE NOT MULTIPLYING BY 2, BUT BOTH HAVE SQUARES i.e. (a)square + 6ab + 9(b)square - 1
1 solutions

Answer 66596 by Earlsdon(6294) About Me  on 2007-08-07 11:13:25 (Show Source):
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Factorise:
a%5E2%2B6ab%2B9b%5E2-1 Rewrite this as:
%28a%5E2%2B6ab%2B9b%5E2%29-1 Factorise the parentheses.
%28a%2B3b%29%28a%2B3b%29-1 which can be written as:
%28a%2B3b%29%5E2-1 Now you have a difference of two squares which can be factored...oops - factorised thus:
A%5E2-B%5E2+=+%28A%2BB%29%28A-B%29 Applying this to your problem,we get:
%28a%2B3b%2B1%29%28a%2B3b-1%29
Check the answer by multiplying the two factors.
Simplify this.
a%5E2%2B3ab%2B3ab%2B9b%5E2-1 Combine like-terms.
a%5E2%2B6ab%2B9b%5E2-1 ...your original expression.


Linear_Equations_And_Systems_Word_Problems/91663: A mother is 30 years older than her daughter. Five years ago she was four times as old as her daughter. How old are they now?
1 solutions

Answer 66568 by Earlsdon(6294) About Me  on 2007-08-06 13:49:48 (Show Source):
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Start by assigning variables to the unknown quantities:
Let M = Mother's present age.
Let D = Daughter's present age.
From the problem description we can write:
Mother's age is (M) is (=) 30 years older than her daughter's age, so:
M = D+30
Five years ago, Mother's age (M-5) was (=) four times her daughter's age, so
M-5 = 4(D-5) Simplify.
M-5 = 4D-20 Rewrite this as: (add 5 to both sides)
M = 4D-15 now substitute this for the M in the first equation.
D+30 = 4D-15 Simplify and solve for D by adding 15 to both sides.
D+45 = 4D Now subtract D from both sides.
45 = 3D Finally, divide both sides by 3.
15 = D or D = 15 This is the daughter's present age.
M = D+30
M = 15+30
M = 45 This is the mother's present age.
Check:
M = D+30
M = 15+30
M = 45
Five years ago:
M-5 = 4(D-5)
45-5 = 4(15-5)
40 = 4(10)
40 = 40


Bodies-in-space/91638: A solid wooden cylinder has a height equal to the diameter of the base circle. This cylinder is then shaved until a sphere is created. If the resultant sphere is the largest possible sphere, determine what proportion of the original cylinder must be discarded in order to produce this sphere. Show working to justify your answer.
1 solutions

Answer 66557 by Earlsdon(6294) About Me  on 2007-08-06 11:26:31 (Show Source):
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Let's start with the appropriate formulas for the volumes of the given solids.
Cylinder:
V%5Bc%5D+=+%28pi%29r%5E2h but the height of the cylinder is given as the length of the diameter (D) of its base and D = 2r where r is the radius of the base. So we can express the volume of the cylinder entirely in terms of the radius (r) of its base, right?
V%5Bc%5D+=+%28pi%29r%5E2%282r%29 Simplifying this we get:
V%5Bc%5D+=+2%28pi%29r%5E3 as the volume of the cylinder.
Sphere:
The largest sphere that could be contained within a cylinder of the dimensions given above i.e., h = 2r and radius r, would be a sphere whose radius is equal to that of the cylinder, or radius r.
The volume of a sphere of radius r is given by:
V%5Bs%5D+=+%284%2F3%29%28pi%29r%5E3
Now all we have to do is to subtract the volume of the sphere from the volume of the cylinder, or V%5Bc%5D-V%5Bs%5D to find the amount of material that must be removed from the wooden cylinder to create the largest possible sphere.
V%5Bc%5D-V%5Bs%5D+=+2%28pi%29r%5E3+-+%284%2F3%29%28pi%29r%5E3 = %282%2F3%29%28pi%29r%5E3


Rational-functions/91647: I have three promblems to answer in a fast time,
add rational expression with common deneminator
subtract and write in lowest terms
I ask the wrong question bummer, here is the correct one
7x-2w/9x - 6x+2w/9x
Thank you for this help
1 solutions

Answer 66556 by Earlsdon(6294) About Me  on 2007-08-06 10:59:27 (Show Source):


Square-cubic-other-roots/91621: This question is from textbook Beginning Algebra
Is the following binomial a difference of squares 9a^2 - 8b^2? I have no idea how to even begin to approach this question. Obviously the answer yes or no would be appreicated, but more importantly why it is such. Thank you in advance.
1 solutions

Answer 66545 by Earlsdon(6294) About Me  on 2007-08-05 22:55:59 (Show Source):
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Is:
9a%5E2-8b%5E2 a difference of squares?
Take a look at each of the two terms:
9a%5E2+=+%283a%29%5E2 This term is a perfect square.
8b%5E2+=+%282b%29%284b%29 This is not a perfect square:
So the answer is no!


Radicals/91615: Will you please help me solve the following problem:
square root x-1=x-7
answer choices:
a. 5
b. 10
c. (1, 2) These are the squiggly parenthesis


1 solutions

Answer 66529 by Earlsdon(6294) About Me  on 2007-08-05 19:57:14 (Show Source):
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Solve:
sqrt%28x-1%29+=+x-7 Square both sides.
x-1+=+x%5E2-14x%2B49 Subtract x from both sides.
-1+=+x%5E2-15x%2B49 Add 1 to both sides.
x%5E2-15x%2B50+=+0 Factor.
%28x-5%29%28x-10%29+=+0 Apply the zero products principle.
x-5+=+0 or x-10+=+0
x = 5 or x = 10


Polynomials-and-rational-expressions/91599: Please HELP!!!!
Solve for x using the quadratic formula. 3x%5E2=5x%2B6
1 solutions

Answer 66518 by Earlsdon(6294) About Me  on 2007-08-05 17:51:42 (Show Source):
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Solve for x using the quadratic formula:
3x%5E2+=+5x%2B6 Subtract 5x+6 from both sides.
3x%5E2-5x-6+=+0 Apply the formula: x+=+%28-b%2B-sqrt%28b%5E2-4ac%29%29%2F2a
x+=+%28-%28-5%29%2B-sqrt%28%28-5%29%5E2-4%283%29%28-6%29%29%29%2F2%283%29
x+=+%285%2B-sqrt%2825%2B72%29%29%2F6
x+=+%285%2B-sqrt%2897%29%29%2F6
The solutions are:
x+=+%285%2F6%29%2Bsqrt%2897%29%2F6
x+=+%285%2F6%29-sqrt%2897%29%2F6