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Polynomials-and-rational-expressions/184661: Melanie can paint a certain barn by herself in x days. Her helper, Melissa can paint the same barn by herself in 2x days. Write a rational expression for the fraction of the barn that they complete in one day by working together. Evaluate the expression for x=5. 1 solutions
Answer 138583 by solver91311(16872) on 2009-03-02 21:22:14 (Show Source):
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Linear-equations/184650: Write an equation in standard form with integer coefficients for the line with slope 13/19 going through the point (-2,-1)
What is the equation of the line 1 solutions
Answer 138575 by solver91311(16872) on 2009-03-02 21:00:26 (Show Source):
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Quadratic_Equations/184612: Linear System Extension Thinking & Inquiry Questions
8. A triangle is formed by the intersection of the lines 2x+3y=14, 4x-5y=-16, and the x-axis. Find the area of the triangle
Could you help me please with this question because i am really confused. Thank you very much!!! 1 solutions
Answer 138556 by solver91311(16872) on 2009-03-02 19:48:49 (Show Source):
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Quadratic_Equations/184560: I'm can't figure out how to create a quadratic equation out of the vertex and a point that it must pass through. All i've managed so far is some trial and error and come up with this.
y=2(x+2)²+4
From the vertex of (-2,4) and passing through (-1,8).
I have been fiddling around with it and have two ideas how to proceed.
I could change (x+2) to something else to move it along the x axis or change the first part of it to change the fatness or whichever you want to call it of the parabola. Regardless i figure there is a better way to do it other then trial and error, if it has been answered before i'm sorry I didn't see it. I'm self taught and this is the first time I really have had any problem.
-Thanks 1 solutions
Answer 138539 by solver91311(16872) on 2009-03-02 18:06:50 (Show Source):
You can put this solution on YOUR website!
If you have three points on a parabola, you can determine the equation of the parabola by substituting the coordinates of your points into:
Giving you three simultaneous linear equations that can be solved for the values of the coefficients A, B, and C.
But you only have two points, namely the vertex and one other point. However, if you use the properties of symmetry for a parabola, you can easily develop the coordinates of the third point.
Your only problem is that you must decide whether your parabola's axis of symmetry is vertical, giving you an equation where y is defined in terms of x, or whether the axis is horizontal, giving you an equation where x is defined in terms of y.
If (-2, 4) is the vertex and (-1,8) is a point on the parabola with a vertical axis of symmetry, there is another point on the parabola with a y value of 8 and the x value that produces it will be equidistant from the vertex on the other side of the vertex from (-1,8), namely (-3, 8).
If this is the case, then:
Solve this system by your favorite method; either Gaussian Elimination or Cramer's Rule should do. The solution set will give you the three required coefficients.
If you think your parabola has a horizontal axis, then your third point is (-1, 0), and you will use:
to set up your three equations.
In the absence of any evidence as to the orientation of the axis of symmetry, you might consider doing the problem both ways.
John

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Graphs/184558: I'm not sure about this.
Graph the linear equation by finding and plotting its intercepts.
y=-5x
Thanks 1 solutions
Answer 138532 by solver91311(16872) on 2009-03-02 17:26:24 (Show Source):
You can put this solution on YOUR website!
The process for finding the intercepts requires substituting 0 for each of the variables and then determining the value of the other variable to give you two points: (a,0) which is the x-intercept (the point where the graph intersects the x-axis and (0,b) which is the y-intercept. This would give you two points that will define the line that is the graph of your equation.
For this equation:
and
The problem you have with the given equation is that the x- and y-intercepts are the same point, namely the origin (0,0), and one point is insufficient to define a line. Consequently, just finding the intercepts is not enough to create the graph of this equation.
To find a second point on the line, you need to find a point that is not an intercept. Select a value for x other than 0, substitute that value, and determine the resulting value for y. The selected value and the resulting value can be formed into an ordered pair that you can graph to establish your second point. (I chose 1 as a value for x, but you could choose anything you like so long as it is not 0)
Now you have two points, (0,0) and (1,-5). Plot them then draw a line through them to give you your graph.
John

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Mixture_Word_Problems/184467: A school district is combining 2 schools that will have a total of 1000 students, 42% of whom are african american. 90% of one school is african american and 10% of the other is african american. How may students are in each school.
I've tried solving it several different ways x/2 + 420 = 1000 and x + y - 420 = 1000 for example and just can't figure this out! Please help - thank you very much! 1 solutions
Answer 138466 by solver91311(16872) on 2009-03-02 02:42:01 (Show Source):
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Polygons/184463: How do I proove that to lines are parallel if I am given a transversal and the angles that transversal is going through the lines? 1 solutions
Answer 138460 by solver91311(16872) on 2009-03-02 01:03:34 (Show Source):
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Quadratic_Equations/184397: Use the quadratic formula to solve the equation:
3x^2-38x=101
a) 19+[664]/3
b) -19+[664]
c) 19-[58]/3
d) 19+[664]/6
e) 19+[58]/3
f) 19-[664]/3
Hint: the [] stands for square root signal. And there is a chance it may be more than one answer!
1 solutions
Answer 138410 by solver91311(16872) on 2009-03-01 19:14:18 (Show Source):
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Geometric_formulas/184399: The height h(in feet) of an object that is dropped from the height of s feet is given by the formula h=s-16t^s, where t is the time the object has been falling. A 5ft woman on a side walk looks directly over head and sees a window washer drop a bottle from the 3 story. How long does she have to get out of the way? Round to the nearest tenth. A story is 12ft.
a) 1.9seconds
b) 1.4seconds
c) 1.7seconds
d) 1.3seconds
1 solutions
Answer 138405 by solver91311(16872) on 2009-03-01 18:44:29 (Show Source):
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