The Math Forum

Search All of the Math Forum:

Views expressed in these public forums are not endorsed by NCTM or The Math Forum.

Math Forum » Discussions » Math Topics » geometry.pre-college

Notice: We are no longer accepting new posts, but the forums will continue to be readable.

Topic: linear equations
Replies: 4   Last Post: Jun 10, 1998 10:57 PM

Advanced Search

Back to Topic List Back to Topic List Jump to Tree View Jump to Tree View   Messages: [ Previous | Next ]
Eileen Schoaff

Posts: 39
Registered: 12/3/04
linear equations
Posted: Dec 4, 1996 12:37 PM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply

Linear equations model many real-life relationships. For some examples, look
at the CBL experiments in the "Real-World Math with the CBL System" book. This
is available from most suppliers of TI calculators and materials. For example,
my class just did the experiment where then measured the pressure at different
depths in a pool. After plotting these points, we could see that the
relationship was linear. We could get the equation for this graph and then
extrapolate. While we went to only 6 ft., we could use the information to
determine the pressure at several 100 ft. down.

Another experiment has students walking to match a given graph. If they have a
slanted line, then they must walk at a constant speed -- which gives the
relationship between velocity and distance. If the distance from an object is
to increase in a linear relationship, then the speed must be constant.

I hope this helps somewhat. Most math books have "problems" that involve
linear equations. And any linear equation, such as 3x+2=7, can be solved by
graphing y = 3x+2 and y = 7. This is especially useful for very complex
equations. Even quadratic equations can be solved this way. For example, to
solve 3x^2 - 2x +7 = 0, first get 3x^2 = 2x - 7, then x^2 = 2/3 x - 7/3. If
you have a graph of x^2, graph the line y = 2/3 x - 7/3 and locate where they
intersect. The intersection is the solution to the quadratic equation --
without having to know how to factor or use the quadratic formula. There is
also linear programming, which uses linear inequalities, to solve problems of
maximizing profit (or something).

Eileen Schoaff
Buffalo State College

Point your RSS reader here for a feed of the latest messages in this topic.

[Privacy Policy] [Terms of Use]

© The Math Forum at NCTM 1994-2018. All Rights Reserved.