Simultaneous Equasions Algebra

Solving Quadratic Equations

I'm looking for the equation of a demand curve, which is usually negative sloping, i.e. y = -x. Well, at least that is how it should look. However, I know that y = -x is a linear equation, and that's not exactly what I need. I guess it could be negatively exponential, but I just don't know. Perhaps it might help to give you a few examples of the points on the curve (points are in x:y format)

1) 1,000:400
2) 1,500:300
3) 2,400:200
4) 4,000:100

I should think that the y-intercept would be around 800. It doesn't matter very much whether the curve touches the x-axis, but I would think that the curve would start approaching it around 8,000 or 9,000.

This is actually the curve that I'm trying to find the equation for. Not only that, but then instead of having it in the format of y = ... , I would need it in the format x = ... If you could show me how to find that, I would appreciate it very much.

Answer:

The curve looks like the top right of a circle as I visualise it. You will find it difficult though to work out the exact equation of the curve.

Perhaps this may help put it in the form x=ay^2+bx+c:

y=ax^2+bx+c

y-c=ax^2+bx

You then have to complete the square:

y-c=sq( rt(a)x+(b/(2rt(a)) ) - b^2/4a (test it by multiplying it out. I may have made a mistake)

y-c+b^2/4a= sq( rt(a)x + (b/2rt(a)) )

rt( y-c+b^2/4a ) =rt(a)x + (b/2rt(a))

rt( y-c+b^2/4a)- (b/2rt(a)) = rt(a)x

<rt( y-c+b^2/4a ) - (b/2rt(a)) >/ <rt(a)>= x

A bit difficult to follow, so suggest writing it out on paper. Have used sq to mean ^2 at times and obviously rt(x) to mean the square-root of x. May be some mistakes here so apologise in advance if so, but gives the general idea on how to isolate x

Online Tutorial Services

PRESS RELEASE– FOR IMMEDIATE RELEASE INNOVATIVE ONLINE TUTORING PROGRAM FOR HIGH SCHOOL STUDENTS IN ALGEBRA I, ALGEBRA II, GEOMETRY Fairview, North Carolina – December 18, 2002 –...

Math Curriculum Provider Releases New Algebra Curriculum and Management System

For Release: Immediately News Release Contact: Anne Lennan, (301) 581-9652, anne@mathrealm.com Premier Math Curriculum Provider Releases New Algebra Curriculum and Management System May 21,...

Learning Piano in Preschool Boosts Long Term Math Skills

Louisville, Kentucky (PRWEB) September 15, 2005 -- Looking for ways to help your child excel long-term in algebra and calculus? A new study released by the University of Louisville suggests starting...

Breakthrough Math Assessment for Algebra Readiness and High School Exit Exam Preparation

Kensington, CA (PRWEB) August 21, 2006 -- Let's Go Learn, Inc. announces its newest assessment in the Diagnostic Online Math Assessment (DOMA) Series: the DOMA Pre-Algebra assessment, designed to...

Horizon Textbook Publishing Releases Understanding Algebra for College Students (4th Edition)

Redding, CA (PRWEB) October 21, 2006 -- Horizon Textbook Publishing (http://www.htpublishing.com) , the leaders in custom textbook publishing for over 20 years, today announced the release of...

MathScore® Adds Significant Algebra Support for Students and Teachers

Palo Alto, Calif. (PRWeb) February 14, 2007 -- In the recently released Curriculum Focal Points report developed by the National Council of Teachers of Mathematics (NCTM), algebra topped the list of...

TRL Software Boosts Math Test Scores, According to Alliant University Study

Palo Alto, Calif. (PRWeb) February 14, 2007 -- In the recently released Curriculum Focal Points report developed by the National Council of Teachers of Mathematics (NCTM), algebra topped the list of...

YourTeacher.com Releases Free Math Instruction Covering Pre-Algebra, Algebra 1, Algebra 2 and Geometry on YouTube

Houston, TX (PRWEB) May 18, 2007 -- YourTeacher.com (www.YourTeacher.com) has released a select number of math videos on YouTube for free. This online math instruction has already been viewed...

Helping Secondary Schools with Pre-Algebra and Exit Exams, Let's Go Learn Releases Pre-Algebra Pathways

Kensington, CA (PRWEB) June 4, 2007 -- Let's Go Learn, Inc. announces the release of its newest online math differentiated instructional software, Pre-Algebra Pathways. Providing a powerful...

DimensionM(TM) Challenging Students with New Evolver Multiplayer Video Game for Algebra: Newest Offering from Tabula Digita Will Be Featured at National Education Computing Conference in First Annual National Multiplayer Educational Game (MEG) Tournament

NEW YORK (BusinessWire EON) June 21, 2007 -- To that end, educational video game company Tabula Digita, www.TabulaDigita.com, today announces the Evolver games for Algebra and Pre-Algebra, the...

YourTeacher.com and Prince George's County Public Schools Team Up to Help At-Risk Students with Math

Upper Marlboro, MD (PRWEB) July 25, 2007 -- Prince George's County Public Schools and YourTeacher.com have teamed up again to help at-risk students with Pre-Algebra, Algebra 1, Geometry, and...