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Topic: Calculate the corner points by using Algebra Solver
Replies: 2   Last Post: Apr 7, 2012 6:14 AM

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 Peter Scales Posts: 192 From: Australia Registered: 4/3/05
Re: Calculate the corner points by using Algebra Solver
Posted: Oct 17, 2011 10:03 AM

> There is a question about algebra. Look at the
> function: -2x+3y<9 and x+y<4. Please calculate the
> corner points. Thanks a lot.
> html

The posts on the site referred to are neither comprehensive nor really helpful.

This is a request to find the range of x and y values to satisfy two inequalities simultaneously. I think the best way to understand the question is to look at it graphically.

Plot the equation for x+y=4
Then the inequality x+y<4 is satisfied by points on one side of the line. The origin is such a point. So all points on the same side of the line as the origin satisfy the inequality.

Next plot -2x+3y=9
Again the origin satisfies the inequality, so all points on the same side of the line as the origin satisfy the inequality.

The two lines intersect at x=3/5, y= 17/5

This value of y is the greatest y value for which both inequalities are satisfied simultaneously. And it is only true if x=3/5

If y=0 then both inequalities are satisfied if -9/2<x<4

And similarly for any other value of y<17/5

You asked about corner points. There is really only one relevant corner: x=3/5, y=17/5

Regards, Peter Scales.

Date Subject Author
10/16/11 yomgigi
10/17/11 Peter Scales
4/7/12 david