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Recent problems solved by 'eggsarecool'

eggsarecool answered: 46 problems
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Linear_Equations_And_Systems_Word_Problems/437485: find the 2 consecutive integers such that the square of the 2nd integer added to the 3 times the 1st is equal to 177
1 solutions

Answer 302626 by eggsarecool(46) About Me  on 2011-04-18 17:44:19 (Show Source):
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Ok so we have two consecutive integers
Lets call the first 1 a, and the second one a+1
Now the formula, %28a%2B1%29%5E2%2B3a=177
So we have the second one squared plus 3 times the first one=177
now we need to solve for a, so we will expand the %28a%2B1%29%5E2
giving us a%5E2%2B2a%2B1%2B3a=177
collect like terms, and move the 177 to the left side.
a%5E2%2B5a-176=0
you can factor this or if you are not comfortable with factoring you can use the quadratic formula x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
Now if we factor we get %28a%2B16%29%28a-11%29=0
which gives us a=-16, a=11
Now I am assuming they wanted the positive intergers, so you have a=11, and then a+1=12. So you integers are 11 and 12


Rational-functions/430398: y=%282x%29%2F%28x%5E2-3x%29
Hi! For this problem, what would the domain be? I am so confused... Please help me! Thank you and have a great day!!! :)
1 solutions

Answer 298920 by eggsarecool(46) About Me  on 2011-04-02 23:52:59 (Show Source):
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Ok, So for functions that are a fraction, the denominator cannot equal zero.
So you solve x%5E2-3x=0 to see what is not allowed, factoring gives you x%28x-3%29=0, and that gives you x=0 and x=3, so x cannot equal 0 or 3. As for how to express this answer
Domain:(-infinity,0)U(0,3)U(3,infinity)


Human-and-algebraic-language/426834: find the two numbers whose sum is 27, such that five times the smaller number is one less than three times the larger number
1 solutions

Answer 297899 by eggsarecool(46) About Me  on 2011-03-29 13:32:32 (Show Source):
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Let's call x the smaller number and y the larger number.
So we have x%2By=27 and 5x=3y-1
Now rearrange the first equation to say y=27-x and substitute into the second equation. 5x=3%2A%2827-x%29-1 -> 5x=81-3x-1 -> 8x=80 -> x=10
Now that we have x plug into 5x=3y-1 to get 5%2A10=3%2Ay-1 50+1=3*y}}}-> 51=3%2Ay -> 17=y
So your ordered pair is (10,17)


Human-and-algebraic-language/427792: The sum of a number and four times its reciprocal is 29/5.Find the number
1 solutions

Answer 297813 by eggsarecool(46) About Me  on 2011-03-28 22:57:14 (Show Source):
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The sum of a number and four times its reciprocal is 29/5.Find the number
Let's call the number n.
The reciprocal would be 1%2Fn
So the formula should look like.
n%2B4%2A%281%2Fn%29=29%2F5
now multiply every term on both sides by n, the 1%2Fn in the 4%2A%281%2Fn%29 will cancel to become 1, leaving you with 4*1=4
n%5E2%2B4=%2829%2F5%29%2An multiply both sides by 5.
5n%5E2%2B20=29n subtract 29n from both sides
5n%5E2-29n%2B20=0 now you have a solvable quadratic equation, that factors into.
%285n-4%29%28n-5%29=0
So n=5 or 5n-4=0 -> 5n=4 divide both sides by 5 n=5%2F4


Human-and-algebraic-language/428488: One number plus sixteen times its reciprocal is equal to ten.
I tried n+16n=10
1 solutions

Answer 297809 by eggsarecool(46) About Me  on 2011-03-28 22:49:17 (Show Source):
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ok so what happened here is that the reciprocal means 1%2Fn
One number plus sixteen times its reciprocal is equal to ten.
So the formula should look like.
n%2B16%2A%281%2Fn%29=10
now multiply every term on both sides by n, the 1%2Fn in the 16%2A%281%2Fn%29 will cancel to become 1, leaving you with 16*1=16
n%5E2%2B16=10n subtract 10n from both sides.
n%5E2-10n%2B16=0 now you have a solvable quadratic equation, that factors into.
%28n-8%29%28n-2%29=0
So +n=8+ or n=2


Geometry_Word_Problems/291783: The length of one leg of a right triangle is 2 cm less than three times the length of other leg. The area of the triangle is 48 cm^2. Find the length of each leg. Please show work! thank u
1 solutions

Answer 210921 by eggsarecool(46) About Me  on 2010-04-13 16:38:07 (Show Source):
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Ok so lets call one leg x
The other leg is three times the length 3x and 2 cm less so 3x-2.
The Area of a triangle is A=%281%2F2%29%2Ab%2Ah
For a right Triangle the base is one leg and the height is the other leg.
We also know that the Area is 48. A=48
So Multiply by 2 to cancel the 1%2F2
96=3x%5E2-2x Subtract 96 from both sides.
3x%5E2-3x-96=0 Factor out the 3.
3%28x%5E2-x-32%29=0 Use the qudratic formula to solve/
Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation ax%5E2%2Bbx%2Bc=0 (in our case 1x%5E2%2B-1x%2B-32+=+0) has the following solutons:

x%5B12%5D+=+%28b%2B-sqrt%28+b%5E2-4ac+%29%29%2F2%5Ca

For these solutions to exist, the discriminant b%5E2-4ac should not be a negative number.

First, we need to compute the discriminant b%5E2-4ac: b%5E2-4ac=%28-1%29%5E2-4%2A1%2A-32=129.

Discriminant d=129 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28--1%2B-sqrt%28+129+%29%29%2F2%5Ca.

x%5B1%5D+=+%28-%28-1%29%2Bsqrt%28+129+%29%29%2F2%5C1+=+6.17890834580027
x%5B2%5D+=+%28-%28-1%29-sqrt%28+129+%29%29%2F2%5C1+=+-5.17890834580027

Quadratic expression 1x%5E2%2B-1x%2B-32 can be factored:
1x%5E2%2B-1x%2B-32+=+1%28x-6.17890834580027%29%2A%28x--5.17890834580027%29
Again, the answer is: 6.17890834580027, -5.17890834580027. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+1%2Ax%5E2%2B-1%2Ax%2B-32+%29


And since you cannot have a negative length in a triangle, 6.17890834580027 is the length of the leg we called x. To find the length of the other leg multiply by 3 and then subtract 2 to get the length of the other leg.
3%2A6.17890834580027-2=16.53672503740081
So the length of the other leg is 16.53672503740081


Trigonometry-basics/285156: Find an equivalent expression for cos 3x in terms of powers of cos x.
cos 3x = cos (2x + x)
= cos 2x cos x - sin 2x sin x <----Using cos(u + v) = cos u cos v - sin u sin v
= (cos^2x - sin^2x) cosx - (2 sinx cosx) sinx
= cos^3x -sin^2x cosx - 2sin^2x cosx
I'm stuck up to here....

1 solutions

Answer 206777 by eggsarecool(46) About Me  on 2010-03-25 10:10:30 (Show Source):
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Going back to this step (cos^2x - sin^2x) cosx - (2 sinx cosx) sinx
You need to use identities 1-%28cos%28x%29%29%5E2=%28sin%28x%29%29%5E2
So %28cos%28x%29%29%5E2-%281-%28cos%28x%29%29%5E2%29-2%28sin%28x%29%29%5E2%2Acos%28x%29
Simplify.
%28cos%28x%29%29%5E2-1%2B%28cos%28x%29%29%5E2-2%281-%28cos%28x%29%29%5E2%29%2Acos%28x%29
2%28cos%28x%29%29%5E2-1-2%28cos%28x%29-%28cos%28x%29%29%5E3%29 And everything is now in terms of cos%28x%29 powers.


Complex_Numbers/285171: Please help me with this problem
(1/3 - i)^2
1 solutions

Answer 206775 by eggsarecool(46) About Me  on 2010-03-25 09:56:48 (Show Source):
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i is defined as the sqrt%28-1%29
So we have.
%281%2F3-sqrt%28-1%29%29%5E2 Now we FOIL.

Simplify.
1%2F9-%282%2F3%29sqrt%28-1%29%2B%28-1%29 note that sqrt%28-1%29%2Asqrt%28-1%29=-1
And now put sqrt%28-1%29 back as i since that is what teachers expect.
1%2F9-%282%2F3%29i-1
So %281%2F3+-+i%29%5E2=1%2F9-%282%2F3%29i-1


Trigonometry-basics/285166: can you show me the steps on how to change the trig identity of tanxcosx=cotx(secx-cosx) ?
1 solutions

Answer 206772 by eggsarecool(46) About Me  on 2010-03-25 09:41:23 (Show Source):
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Ok so lets rewrite everything in terms of sin%28x%29 and cos%28x%29
So we have
Multiply everything out.
sin%28x%29=%281%2Fsin%28x%29%29-%28cos%28x%29%29%5E2%2Fsin%28x%29 common denominator of sin%28x%29 on the right.
sin%28x%29=%281-%28cos%28x%29%29%5E2%29%2Fsin%28x%29 we know that 1-%28cos%28x%29%29%5E2=%28sin%28x%29%29%5E2
So sin%28x%29=%28sin%28x%29%29%5E2%2Fsin%28x%29
sin%28x%29=sin%28x%29


test/285170: evaluate given function for f(3) and f(-2) f(x)=x^2+4x-1
1 solutions

Answer 206770 by eggsarecool(46) About Me  on 2010-03-25 09:33:14 (Show Source):
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f%283%29 means plug in 3 for x so we get f%283%29=%283%29%5E2%2B4%2A%283%29-1=9%2B12-1=20
So f%28-2%29=%28-2%29%5E2%2B4%2A%28-2%29-1=4-8-1=-5


Graphs/285162: Determine whether the graphs of the equations are perpendicular. 5x-8y=3, 5y-8x=2. Are the graphs of the given equations perpendicular?
1 solutions

Answer 206769 by eggsarecool(46) About Me  on 2010-03-25 09:30:32 (Show Source):
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To do this you need to solve both equations for y, once you have done this you will be able to see the slopes and that will tell you if they are perpendicular.
So 5x-8y=3 add 8y to both sides.
5x=8y%2B3 subtract 3 from both sides.
5x-3=8y And divide through by 8.
%285%2F8%29%2Ax-3%2F8=y So the slope is m=5%2F8 that comes from the number attached to the x.
For the next equation.
5y-8x=2 Add 8x to both sides.
5y=8x%2B2 And divide through by 8.
y=%288%2F5%29%2Ax%2B2%2F5
So the slope is m=8%2F5
The definition for two lines to be perpendicular is that the slope of one must be the negative reciprocal of the slope of the other. The negative reciprocal of 5%2F8 is -8%2F5 and we only got 8%2F5 so they are not perpendicular.


Graphs/285160: solve inequality. express answer in interval notation..
-3 <= 3 - 2x <= 9
1 solutions

Answer 206767 by eggsarecool(46) About Me  on 2010-03-25 09:20:56 (Show Source):
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-3%3C=3+-+2x%3C=+9 The first step will be to subtract 3 from all 3 parts.
-6%3C=-2x%3C=6 Now divide by -2. And remember to reverse the <= signs when dividing by a negative.
3%3E=x%3E=-3
Expressed in interval notation this is [-3,3]


Linear-equations/284715: the line passes thru (4,-7) and is perpendicular to the line whose equation is x-2y=3
write an equation in slope intercept form satisfying the given conditions
1 solutions

Answer 206571 by eggsarecool(46) About Me  on 2010-03-24 10:06:52 (Show Source):
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The first step in such a problem is to solve the given equation for y.
x-2y=3 So subtract x from both sides.
-2y=3-x Now divdie everything by -2.
y=-3%2F2+%2B+%281%2F2%29%2Ax The number attached to the x is the slope of this line, 1%2F2 To get a line that is perpendicular you need to take the negative reciprocal which would be -2%2F1 or just -2.
We now do y=mx%2Bb m stands for slope so we have.
y=-2x%2Bb Now you plug in (4,-7), 4 for x and -7 for y to get the line that passes through that point and solve for b.
-7=-2%2A4%2Bb
-7=-8%2Bb add 8 to both sides.
1=b
Going back to y=-2x%2Bb you will now put in the b you found.
And y=-2x%2B1 is your final answer.


Miscellaneous_Word_Problems/284748: A student may pay $1.50 for a single bus ticket or $5.75 for a package of 5 tickets. If a student requires 40 tickets, how much does she save by buying all of the tickets in packages of 5 rather than buying 40 single tickets?
(A) $54.25 (B) $34.00 (C) $14.00 (D) $8.25 (E) $4.25
1 solutions

Answer 206567 by eggsarecool(46) About Me  on 2010-03-24 09:51:00 (Show Source):
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Ok so to buy 40 tickets in packets of 5 means youe need 8 packets. 8%2A5=40
So 8 packets of 5 tickets costs 8%2A5.75=46. So 40 tickets in packets costs $46
Now for single tickets 40%2A1.50=60. So buying 40 single tickets costs $60
The differance is the ammount he saves 60-46=14. So he saves $14
Which is answer C


Coordinate-system/237326: what is the equation of the line tangent to the circle x^2+y^2=25 at the point (3,4) ?
I don't know how to go about this sum. Please solve and explain
thanks
1 solutions

Answer 174522 by eggsarecool(46) About Me  on 2009-11-10 12:11:17 (Show Source):
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You need to implicit differentiation for this problem and solve for dy%2Fdx
So we have.
x%5E2%2By%5E2=25
The derivative is 2x%2B2y%2Ady%2Fdx=0 the 2y produces the dy%2Fdx because y is a function so you have to apply the chain rule to it.
So now.
2y%2Ady%2Fdx=-2x
dy%2Fdx=-2x%2F2y
dy%2Fdx=-x%2Fy
And x and y are given by (3,4) giving x=3 and y=4. (x%5B1%5D,y%5B1%5D)
So dy%2Fdx=-%283%2F4%29
Now for the tangent line you have.
y-y%5B1%5D=%28dy%2Fdx%29%28x-x%5B1%5D%29
so we have y-4=-%283%2F4%29%28x-3%29
Giving us y-4=-%283%2F4%29x%2B9%2F4 Add 4 to both sides. 4 can be rewritten as 16%2F4
y=-%283%2F4%29x%2B9%2F4%2B16%2F4
y=-%283%2F4%29x%2B25%2F4
And that is your tangent line.


expressions/237328: What is the simplified solution to -2^2-(-2)^3? And what are the steps?
1 solutions

Answer 174519 by eggsarecool(46) About Me  on 2009-11-10 11:59:09 (Show Source):
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I am assuming you did not lose any parentheses. So this has to do with order of operations.
-2%5E2-%28-2%29%5E3 parentheses take precedence over everything and then exponents take precedence over multiplication and subtraction.
For the first term you square first and then multiply.
But for %28-2%29%5E3 you have to cube -2 before multiplying by -1.
So we have -2%2A2-%28-2%29%2A%28-2%29%2A%28-2%29=-4-%28-8%29=-4%2B8=4


Trigonometry-basics/237320: PLEASE HELP ME SOLVE THIS TRIGONOMETRIC FUNCTIONS:
Given that sin0=-1/2 and 0 lies in quadrant lV,find the following value.sec 0
the possible answers are:
a)-2
b)square root of 3/2 sqrt%283%2F2%29
c)(2/square root of 3)/3 %282sqrt%283%29%29%2Fsqrt%283%29
1 solutions

Answer 174517 by eggsarecool(46) About Me  on 2009-11-10 11:53:03 (Show Source):
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I am going to replace theta with x since i have no way to make the computer display theta.
So what we have is.
sin%28x%29=-%281%2F2%29
The referance angle that makes sin equal to 1%2F2 is 30 degress or pi%2F6
If we want this angle in the 4th qudrant we get 360-30=330 or 2pi-pi%2F6=11pi%2F6
So we know that our angle is 330 degrees or 11pi%2F6
We also know that sec%28x%29=1%2Fcos%28x%29 So we need to find out what cos(x) is to find sec(x).
So we need to find cos of 330 degrees. The referance angle was 30 degrees and cos%2830%29=sqrt%283%29%2F2. Cos is positive in the 4th quadrent so cos%28330%29=sqrt%283%29%2F2
And sec%28x%29 is 1%2Fcos%28x%29
So sec%28330%29=1%2F%28sqrt%283%29%2F2%29=2%2Fsqrt%283%29
And if you rationalize this.
%282%2Fsqrt%283%29%29%2A%28sqrt%283%29%2Fsqrt%283%29%29=%282sqrt%283%29%29%2F3
So choice C is the correct answer.


Linear-equations/237318: 4v-%28v-2%29=7-2%283v-4%29
1 solutions

Answer 174511 by eggsarecool(46) About Me  on 2009-11-10 11:38:03 (Show Source):
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4v-%28v-2%29=7-2%283v-4%29
Ok so distribute first to remove parentheses.
4v-v%2B2=7-6v%2B8 Now combine like terms.
3v%2B2=15-6v Add 6v to both sides.
9v%2B2=15 Subtract 2 from both sides.
9v=13 And divide both sides by 9.
v=13%2F9


Triangles/237317: For a right triangle, what is the area with side A of 12 and the side B of 10?
1 solutions

Answer 174509 by eggsarecool(46) About Me  on 2009-11-10 11:35:06 (Show Source):
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The area of a triangle is A=%281%2F2%29%2Abase%2Aheight
Now for a right triangle sides A=12 and B=10 are the base and the height.
So your area is A=%281%2F2%29%2A12%2A10=60
So the area of your triangle is 60.


Numeric_Fractions/237314: 2%2F%283x-7%29=5, two over three x -7 = 5
or 2%2F3x+-+7=5
1 solutions

Answer 174506 by eggsarecool(46) About Me  on 2009-11-10 11:32:04 (Show Source):
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Not sure which you wanted so I will solve both.
For
2%2F%283x-7%29=5we will multiply both sides by 3x-7
Giving us 2=5%283x-7%29
When we distribute the 5
2=15x-35 Now add 35 to both sides.
37=15x
and divide both sides by 15.
x=37%2F15
Now the other interpretation of your problem.
2%2F3x+-+7=5 For this one you would need to get a common denominator first.
So 2%2F3x-%287%2A3x%29%2F3x=5
With the common denominator we have.
%282-21x%29%2F3x=5 Now we will multiply both sides by 3x.
Giving us 2-21x=5%2A3x=15x Add 21x to both sides.
2=36x Divide both sides by 36.
x=2%2F36=1%2F18


Quadratic_Equations/234434: translate the problem into a pair linear equations in two variables.solve using elimination or substitution.
andy has 14 coins made up of quarters and half dollars, and their total value is $4.25.How many quarters does he have?

1 solutions

Answer 172845 by eggsarecool(46) About Me  on 2009-11-02 22:53:28 (Show Source):
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Ok so lets say that Andy has x quarters and y half dollars.
So x%2By=14
And now for the values of the coins.
0.25%2Ax%2B0.5%2Ay=4.25 Each quarter is worth 0.25 and you multiply by x, and each half dollar is worth 0.5 and you multiply by y. When you add them up you get the amount the coins are worth.
So x=14-y
Putting this into the second equation gives us.
0.25%2814-y%29%2B0.5y=4.25 Distributing the 0.25 gives us.
3.5-0.25y%2B0.5y=4.25 Combine like terms.
0.25y%2B3.5=4.25 Subtract 3.5 from both sides.
0.25y=0.75 Divide both sides by 0.25.
y=3 We now know that y=3 and we can plug this into x=14-y to gives us x=14-3=11
So y=3 and x=11


Numbers_Word_Problems/234098: The sum of two numbers equals eighteen. The total of three times the smaller and two times the larger is 44.

1 solutions

Answer 172666 by eggsarecool(46) About Me  on 2009-11-02 11:34:34 (Show Source):
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The sum of two numbers equals eighteen. The total of three times the smaller and two times the larger is 44.
Ok so we have two unknown numbers. We will call the smaller one x and the larger one y.
So x%2By=18 and 3x%2B2y=44
Now we have a system of equations.
And we can write x=18-y
Now when you see x in the second equation replace it with 18-y
This gives us.
3%2818-y%29%2B2y=44
48-3y%2B2y=44 Subtract 48 from both sides.
-y=-4 Divide both sides by -1.
y=4
And x was 18-y so x=18-4=14
So x=14 and y=4


Polynomials-and-rational-expressions/234082: what does it mean to refer to a 20-in TV set or a 25-in TV set? Such units refer to the diagonal of the screen. A 15-in TV set also has a width of 12 inches. What is its height? What is the height of a 15-in TV?
1 solutions

Answer 172663 by eggsarecool(46) About Me  on 2009-11-02 11:12:39 (Show Source):
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This problem is done using the Pythagoran theorem. Which says that a%5E2%2Bb%5E2=c%5E2
This says that the two shorter sides of a right triangle squared equal the long side squared

And the triangles longest side is the diagnol line across the tv set.
So we know the diagnol of the tv is 15, so c=15
And we know the leangth is 12 so a=12
This gives you that 15%5E2=12%5E2%2Bb%5E2
225-144=b%5E2
b%5E2=81
b=9
Since b is the height of your triangle the height is 9.


logarithm/234094: solve for x:
59.2=42.5(1.64)^x
1 solutions

Answer 172662 by eggsarecool(46) About Me  on 2009-11-02 11:06:16 (Show Source):
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solve for x:
59.2=42.5%281.64%29%5Ex
So first we divide both sides by 42.5
1.39=%281.64%29%5Ex
Now we will take ln of both sides. This helps because there is a property of logarithms that says the following ln%28a%29%5Eb=bln%28a%29 In english it basically allows you to take the exponent outside the logarithm.
So applying this to our equation gives us.
ln%281.39%29=ln%281.64%29%5Ex
Now I will move the x outside.
ln%281.39%29=xln%281.64%29
Now all that is left is to divide both sides by ln%281.64%29
%28ln%281.39%29%2Fln%281.64%29%29=x
Using a calculator you can get a decimal value of.
x=0.666


Linear-equations/233545: write equation,in slop-intercept from,(3,4)and(5,8)
1 solutions

Answer 172400 by eggsarecool(46) About Me  on 2009-11-01 01:25:54 (Show Source):
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Ok so first we need the slope. You compute this using m=%28y%5B2%5D-y%5B1%5D%29%2F%28x%5B2%5D-x%5B1%5D%29 Where m is your slope.
So you have (3,4) and (5,8)
Giving us x%5B1%5D=3 y%5B1%5D=4 x%5B2%5D=5 y%5B2%5D=8
So m=%288-4%29%2F%285-3%29=4%2F2=2
Now to write the the equation you can pick (3,4) or (5,8)
So it will look like y-y%5B1%5D=m%28x-x%5B1%5D%29 or y-y%5B2%5D=m%28x-x%5B2%5D%29
I will use the first point (3,4).
So now we have y-4=2%28x-3%29
Next multiply out the two on the right hand side. y-4=2x-6
Now add 4 to both sides.
This gives you your final answer of y=2x-2


Geometric_formulas/232854: what would the answer be for 1%2F2t=-7
1 solutions

Answer 171968 by eggsarecool(46) About Me  on 2009-10-29 11:50:15 (Show Source):
You can put this solution on YOUR website!
Ok so we have 1%2F2t=-7 What you can do in algebra is flip both sides of an equation. So 1%2F2t will become 2t%2F1 and -7 which is really -7%2F1 will become -1%2F7
So now we have.
2t=-1%2F7 Now you divide both sides by two. Dividing a fraction can be confusing so you can multiply by 1%2F2 instead of dividing by 2.
t=%28-1%2F7%29%2A%281%2F2%29
Giving us.
t=-1%2F14


Systems-of-equations/232857: A motel charges 80.00 per day for double occupancy and 70 pr day for single occupancy. If 80 rooms are occupied one night for a total of 5800.00 how many rooms of each type are occupied?
1 solutions

Answer 171967 by eggsarecool(46) About Me  on 2009-10-29 11:44:51 (Show Source):
You can put this solution on YOUR website!
A motel charges 80.00 per day for double occupancy and 70 pr day for single occupancy. If 80 rooms are occupied one night for a total of 5800.00 how many rooms of each type are occupied?
Ok I am goint to define x as the number of single occupancy rooms. And what this tells us is that 80-x is the number of double occupancy rooms.
So now we set up the equation.
70%2Ax%2B%2880-x%29%2A80=5800 So it is the number of single occupancy rooms times the single rate + the number of double occupancy rooms times the double rate = to the total amount made by the hotel.
Solving the equation.
70x%2B80%2A80-80x=5800
-10x%2B6400=5800 Subtract 6400 from both sides.
-10x=-600 And divide both sides by -10.
x=60 this tells us that there were 60 single occupancy rooms since I defined x as single occupancy. And double occupancy was 80-x, so 80-60=20 So there must be 20 double occupancy rooms.


Trigonometry-basics/232805: Please help prove identity:
2sin%282x%29cos%282x%29=4cos%28x%29%28sin%28x%29-2%28sin%28x%29%29%5E3%29
thank you
1 solutions

Answer 171966 by eggsarecool(46) About Me  on 2009-10-29 11:37:19 (Show Source):
You can put this solution on YOUR website!
2sin%282x%29cos%282x%29=4cos%28x%29%28sin%28x%29-2%28sin%28x%29%29%5E3%29
Two formulas you need are sin%282x%29=sin%28x%29cos%28x%29 and the other is cos%282x%29=1-2%28sin%28x%29%29%5E2%29
Using these we can rewrite the left side to become.
2%2A2sin%28x%29cos%28x%29%281-2%28sin%28x%29%29%5E2%29 2%2A2=4
4sin%28x%29cos%28x%29%281-2%28sin%28x%29%29%5E2%29 Now we distribute the sin%28x%29 that is on the outside.
4cos%28x%29%28sin%28x%29-2%28sin%28x%29%29%5E3%29 this proves your identity.


Polynomials-and-rational-expressions/232845: find:
2x/(x^2-9) + (1-2x)/(x^2-4x+3)
1 solutions

Answer 171965 by eggsarecool(46) About Me  on 2009-10-29 11:23:54 (Show Source):
You can put this solution on YOUR website!
I am assuming you want this solved for 0
2x%2F%28x%5E2-9%29+%2B+%281-2x%29%2F%28x%5E2-4x%2B3%29=0 So first we need a common denominator
We will start by factoring the current denominators.
2x%2F%28x%2B3%29%28x-3%29%2B%281-2x%29%2F%28x-3%29%28x-1%29=0
Now for the common denominator.
Now your denominator cannot equal to zero since you are not allowed to divide by 0. so x cannot equal to 1, 3, or -3.
Since the bottom cannot equal 0 the only time the fraction will equal 0 is when the numerator equals 0.
Now we multiply out the numerator.
%282x%5E2-2x%2Bx%2B3-2x%5E2-6x%29%2F%28x%2B3%29%28x-3%29%28x-1%29=0
Next we combine like terms.
%28-7x%2B3%29%2F%28x%2B3%29%28x-3%29%28x-1%29=0
Now we set the numerator equal to 0 and solve.
-7x%2B3=0 Add 7x to both sides.
7x=3 Divide both sides by 7.
x=3%2F7


Numeric_Fractions/232846: I need help with COMPLETELY factoring out the polynomial 3x3-12x
1 solutions

Answer 171961 by eggsarecool(46) About Me  on 2009-10-29 11:07:08 (Show Source):
You can put this solution on YOUR website!
I need help with COMPLETELY factoring out the polynomial 3x%5E3-12x
Ok first step would be to factor out 3x which leaves us with
3x%28x%5E2-4%29 Now we can use the differance of squares formula which says that a%5E2-b%5E2=%28a-b%29%28a%2Bb%29
For us a=x and b=-2
This gives us 3x%28x%5E2-4%29=3x%28x%2B2%29%28x-2%29 we factored the x%5E2-4 using difference of squares.


Expressions-with-variables/232481: solve for the variable, first stating any restrictions. if there are no restrictions, state that
7/x+4 + 2/x-3 = 7x-21/x^2+x-12
1 solutions

Answer 171791 by eggsarecool(46) About Me  on 2009-10-28 13:07:21 (Show Source):
You can put this solution on YOUR website!
I am assuming this is the original problem, it wasn't completely clear.
7%2F%28x%2B4%29+%2B+2%2F%28x-3%29+=+%287x-21%29%2F%28x%5E2%2Bx-12%29 the next step is to rewrite the right hand side.
7%2F%28x%2B4%29+%2B+2%2F%28x-3%29+=+%287x-21%29%2F%28x%2B4%29%28x-3%29 Now we state the restrictions, these happen when you divide by 0. So x cannot equal to 3 or -4
Your next step is to create a common denominator on the left side.

Now we will only pay attention to the numerators since the denominators match.
This gives us.
7x-21%2B2x%2B8=7x-21
Now combine like terms.
9x-13=7x-21
subtract 9x from both sides.
2x-13=-21
add 13 to both sides
2x=-8
Divide both sides by 2.
x=-4
This gives you the solution x=-4 but since this is among the values that are not allowed your equation has no solution.