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Polynomials-and-rational-expressions/194815: This question is from textbook Elementary and Intermediate Algebra
If each of the sides of a square is lengthened by 4m, the area becomes 49m^2. Find the length of the side of the original.
1 solutions

Answer 146151 by solver91311(16868) About Me  on 2009-05-04 23:53:26 (Show Source):
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If the area of a square is 49, then the length of a side must be 7.


John



Quadratic_Equations/194813: The question I have is how to determine the domain, such as in the question: State the domain in the function f(x)= 3x-6/x^2-25.
1 solutions

Answer 146150 by solver91311(16868) About Me  on 2009-05-04 23:50:05 (Show Source):
You can put this solution on YOUR website!

The domain is that set of values for which the function is defined. You have a rational function, so you need to find any values for which the denominator would be zero. Then the domain is everything else.

Set the denominator equal to zero:



Factor the difference of two squares:



So the denominator is zero if

Hence, the domain is all real numbers except for 5 and -5. In set builder notation:





John



Quadratic_Equations/194754: Solve using the quadratic methods. Thanks!
(x+4)^4-(x+4)^2-6=0
1 solutions

Answer 146147 by solver91311(16868) About Me  on 2009-05-04 23:42:34 (Show Source):
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Let



Factor:



or



So:










John



Polygons/194786: This question is from textbook McDougal Littell Geometry
A regular hexagonal shaped target with sides of length 14 centimeters has a circular bull's eye with a diameter of 3 centimeters. What is the probability that a dart that hits the target will hit the bull's eye?
1 solutions

Answer 146142 by solver91311(16868) About Me  on 2009-05-04 23:23:05 (Show Source):
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The probability is the area of the circle divided by the area of the hexagon.


John



Quadratic-relations-and-conic-sections/194808: i have to write the equation of the conic section in standard form and classify the conic section:
9y^2-x^2+2x+54y+62=0
1 solutions

Answer 146141 by solver91311(16868) About Me  on 2009-05-04 23:20:17 (Show Source):
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This one is already in standard form. But notice that the signs on the two second degree terms are opposite. That means this is a hyperbola.

John



Miscellaneous_Word_Problems/194792: The sum of two numbers is -42. The first number minus the second number is 52. Find the numbers?
1 solutions

Answer 146140 by solver91311(16868) About Me  on 2009-05-04 23:17:47 (Show Source):
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Solve the system. Hint: Use the Elimination method.

John



Reduction-of-unit-multipliers/194807: It says perform the following unit conversions.
3 3/4yd.=____in.
The only thing so far that I come up with is:15/4=3.75
I cannot figure out what to do next.
Please help.
Thanks,
Kathy Price
1 solutions

Answer 146138 by solver91311(16868) About Me  on 2009-05-04 23:15:53 (Show Source):
You can put this solution on YOUR website!


There are 36 inches in a yard. Since for the same distance, you are going to have a larger number of inches than yards, you should multiply:



You can do your own arithmetic.


John



Miscellaneous_Word_Problems/194791: If a ball is tossed into the air from a height of 6 feet with a velocity of 32 feet per second, then its altitude at time t (in seconds) can be described by the function A(t)=-15t+32t+6.
Find the altitude of the ball at 2 seconds
1 solutions

Answer 146136 by solver91311(16868) About Me  on 2009-05-04 23:13:03 (Show Source):
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I don't know where you got the altitude function that you stated, but it is incorrect (even if you are on a different planet - you still need to square the variable in the first term). What you want is:



You need to find A(2):



You can do your own arithmetic.


John



Equations/194793: This question is from textbook algebra 1/2
how do you find the latral surface?
1 solutions

Answer 146134 by solver91311(16868) About Me  on 2009-05-04 23:07:52 (Show Source):
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I think you meant lateral surface area. Trouble is, you don't specify the shape for which you want the lateral surface area. In general, in that lateral means "side," it is the surface area of the figure excluding the bases.

John



Miscellaneous_Word_Problems/194794: the perimeter of a lot is 190 m. the length os four times the width. find the length and the width?
1 solutions

Answer 146132 by solver91311(16868) About Me  on 2009-05-04 23:04:28 (Show Source):
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Let x represent the width. Then 4x represents the length. The perimeter of a rectangle is two times the width plus two times the length:



Solve for x to get the width, multiply that by 4 to get the length.

John



Circles/194796: if the diameter of a circle is 16 centimeters.What is the radius
1 solutions

Answer 146130 by solver91311(16868) About Me  on 2009-05-04 23:01:05 (Show Source):
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The radius is always half of the diameter.

John



Trigonometry-basics/194801: I'm trying to plot points on a graph. the problem is y=3sec4x. I have all the points but one. I'm stuck at 5 pi/2. I have no idea how to find this on the unit circle. Explain plz?
1 solutions

Answer 146129 by solver91311(16868) About Me  on 2009-05-04 22:59:03 (Show Source):
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From the positive x-axis to the positive y-axis: , then from the positive y-axis to the negative x-axis another for a total of . Then one more quarter circle, . All the way back to the beginning: . Yep, is the same thing as . In fact, all angles of the form are the same angle


John



Inverses/194805: 8+(a+6)=(8+a)+6
1 solutions

Answer 146126 by solver91311(16868) About Me  on 2009-05-04 22:49:17 (Show Source):
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Very interesting illustration of the Associative Property of Addition. Did you have a question about it?


John



Quadratic_Equations/194804: please help me solve this equation: -8n(10n-1)=0
please help me i'm stuck.
1 solutions

Answer 146124 by solver91311(16868) About Me  on 2009-05-04 22:48:04 (Show Source):
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Use the Zero Product Rule: If then or .

So either which means that or

which means that

John



Quadratic-relations-and-conic-sections/194803: (x+5)2= -(y-9)
1 solutions

Answer 146123 by solver91311(16868) About Me  on 2009-05-04 22:45:19 (Show Source):
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Is there a question in there somewhere?


John



Linear-equations/194799: i have two solution sets from two linear equations
equation one:
y=4(x)-1
The solution set is:
(-2, -9)
(0, -1)
(2, 7)
(5, 19)
Equation 2:
y=3(x)+5
The solution set is:
(-2, 9)
(0,15)
(2, 21)
(5, 30)
As you can see I have already found the solution set; my problem is that once I graph it I can not get them to cross to show the solution point. Can you please help me?
1 solutions

Answer 146122 by solver91311(16868) About Me  on 2009-05-04 22:44:01 (Show Source):
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Since y is equal to two different things, why not set them equal to each other?



Add -3x to both sides, add 1 to both sides:



Then



Point of intersection is (6, 23)




John



Circles/194798: __
AB is tangent to circle O at A(not drawn to scale) find the length of the radius r, to the nearest tenth.
1 solutions

Answer 146120 by solver91311(16868) About Me  on 2009-05-04 22:28:57 (Show Source):
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Not near enough information.


Quadratic-relations-and-conic-sections/194756: Is this correct: What is the equation of a parabola with vertex (0,0) and focus (0,4)?
%28x-h%29%5E2+=+4p%28y-k%29
%28x-0%29%5E2+=+4%284%29%28y-0%29
%28x-0%29%5E2+=+16%28y-0%29
If not where did I go wrong?
1 solutions

Answer 146106 by solver91311(16868) About Me  on 2009-05-04 20:37:26 (Show Source):
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You are spot on, except that I would have gotten rid of the zeros in the final form.



John



Polynomials-and-rational-expressions/194761: Please Rationalize the denominator and simplify
√6/4√3+√2

1 solutions

Answer 146103 by solver91311(16868) About Me  on 2009-05-04 20:10:32 (Show Source):
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Please use parentheses in the future so that we don't have to guess at what you meant. I presume you meant:



Multiply by 1 in the form of the conjugate of the denominator divided by itself:




John



Quadratic_Equations/194736: Hello,
I have been working on this problem for a while and can;t seem to come up with a reasonable solution.
The Hudson River flows at a rate of 5 miles per hour. A patrol boat travels 40 miles upriver, and returns in a total time of 6 hours. What is the speed of the boat in still water?
D=R x T
r=40/6
r-5=40/6
40/r-5 + 40/r+5=6
r^2-25(40/r-5) + r^-25(40/r+5=6
40r^2+1000/r^2-25 + 40r^2-1000/r^2-25=6
(r-5)(r+5) 40/r-5 and (r-5)(r+5) 40/r+5
after cancelling: 40r+5 +40r-5=6
80r=6
r=74
I know that this is not correct, but I can't figure out where I went wrong.
Thanks,
Dave
1 solutions

Answer 146101 by solver91311(16868) About Me  on 2009-05-04 20:01:51 (Show Source):
You can put this solution on YOUR website!

You got off on the wrong foot from the git-go. You said , but that can't be true because 40 is the one-way distance and 6 hours is the total time for both directions. Not to mention that you then said and both of those statements cannot be simultaneously true.

Let's begin anew.

Let r represent the speed of the boat in still water. Then r - 5 is the speed of the boat upriver (against the current) and r + 5 is the speed downriver. Let t represent the amount of time it took to go upriver, then 6 - t is the time it took to go downriver.

For the upriver trip:



and for the downriver trip:



Solving both equations for t we get:



and



Now that we have two things equal to t, we can set them equal to each other:



LCD is , so:



Expanding binomials, removing parentheses, collecting terms:



Now, you can either multiply both sides by or realize that if you have two equal fractions with identical denominators, then the numerators have to be equal as well to write:



Put in standard form:



Fortunately, this little puppy factors rather neatly:




Exclude the negative root because we are reasonably certain that the boat wasn't going backwards as a negative rate through the water would suggest, and the rate in still water is 15 mph.

Check:

A 40 mile upriver trip would take 40 divided by (15 - 5) = 4 hours. A 40 mile downriver trip would take 40 divided by (15 + 5) = 2 hours. Total time: 6 hours, answer checks.

John



Volume/194744: The figure is 4 cubes long, and 2 cubes wide, and three cubes high. what is the volume of the figure?
1 solutions

Answer 146097 by solver91311(16868) About Me  on 2009-05-04 19:24:02 (Show Source):


Polynomials-and-rational-expressions/194747: A square with sides of 50 feet.What is the shortest distance between two opposite vertices?
1 solutions

Answer 146096 by solver91311(16868) About Me  on 2009-05-04 19:23:02 (Show Source):
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Remember Pythagoras?




John



Quadratic-relations-and-conic-sections/194741: Identify the following conic. That is, circle, parabola, hyperbola or ellipse?
x2 - 4y2 - 4x - 24y = 48
1 solutions

Answer 146095 by solver91311(16868) About Me  on 2009-05-04 19:19:53 (Show Source):
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The high order terms have opposite signs, therefore it is a hyperbola.


John



Linear-equations/194710: the sum of the length and the width of a rectangular region is equal to 84 feet, whereas the corresponding positive difference is 19feet. Find the area of he enclosed rectangular region
(use a 2-variable approach)
1 solutions

Answer 146089 by solver91311(16868) About Me  on 2009-05-04 18:11:40 (Show Source):
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Let x represent the length and let y represent the width, then:



and



Solve the system (all set up for the elimination method, just add the equations). Once you have the values for length and width, take the product to find the area.


John



logarithm/194725: log2(3x+1)=3
1 solutions

Answer 146087 by solver91311(16868) About Me  on 2009-05-04 18:06:31 (Show Source):
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Remember that:



So:









John



Linear-equations/194705: Graph the Linear equation
4x-5y=60
1 solutions

Answer 146085 by solver91311(16868) About Me  on 2009-05-04 18:02:32 (Show Source):
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Step 1: Pick a value for x.

Step 2: Substitute that value into the equation in place of x and then solve for y.

Step 3: Create an ordered pair from the value you selected in step 1 and the value you calculated in step 2. Plot that point on your graph.

Step 4: Repeat steps 1 through 3 using a different value for x.

Step 5: Draw a line across your graph connecting the two plotted points.

Done.

John



Rational-functions/194724: This question is from textbook prentice hall mathematics
9(x+2)(2x-1)and3(x+2)
1 solutions

Answer 146083 by solver91311(16868) About Me  on 2009-05-04 17:58:50 (Show Source):
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Was there a question there somewhere?


John



Miscellaneous_Word_Problems/194704: Sally and Tom are good friends. Sally is 7 years older than Tom. Next year she will be twice as old as him. How old are Sally and Tom right now?
1 solutions

Answer 146082 by solver91311(16868) About Me  on 2009-05-04 17:57:48 (Show Source):
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So



Extra credit: How old would they be if they were NOT good friends?


John



Quadratic_Equations/194712: Evaluate the functions for the values of x given as 1, 2, 4, 8, and 16. Describe the differences in the rate at which each function changes with increasing values of x. And then rank them fastest to slowest using the problem numbers.
f(x) = 2x – 5
f(x) = x2 - 4x + 3
f(x) = x3 + 4x2 - 2x - 3
f(x) = 7x
f(x) = log x
1 solutions

Answer 146081 by solver91311(16868) About Me  on 2009-05-04 17:51:18 (Show Source):
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Just substitute the given numbers for x and do the arithmetic. I hope you didn't expect someone to do these 25 calculations for you.

John



Probability-and-statistics/194718: If there is 28 movies and 12 of those are westerns and 16 are sci-fi what is the probability of picking 3 sci fi.
1 solutions

Answer 146080 by solver91311(16868) About Me  on 2009-05-04 17:48:59 (Show Source):
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It depends on whether or not you replace the one you selected each time.


John



Polynomials-and-rational-expressions/194715: 2x^2 + 5x - 6 = 0
how do you do the step by step factorising?
thanks!
1 solutions

Answer 146079 by solver91311(16868) About Me  on 2009-05-04 17:47:41 (Show Source):
You can put this solution on YOUR website!


In a word, you don't. This quadratic trinomial does not factor over the integers. How do I know? Square the coefficient on the first degree term -- 5 squared is 25. Multiply -4 times the coefficient on the high order term times the constant, -4 times 2 times -6 is 48. Combine that with the previous result, 25 plus 48 = 73. 73 is NOT a perfect square, so the polynomial doesn't factor over the integers.

John