SOLUTION: Find the equation of the linear function that contains the points (1, 4) and (3, −2).

Algebra ->  Functions -> SOLUTION: Find the equation of the linear function that contains the points (1, 4) and (3, −2).      Log On


   

Question 1163956: Find the equation of the linear function that contains the points (1, 4) and (3, −2).
Found 3 solutions by solver91311, greenestamps, Alan3354:
Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!


Use the two-point form of an equation of a line:



Where and are the given points.

Since you are asked for a linear function you want to rearrange your derived equation to be in form.


John

My calculator said it, I believe it, that settles it

Answer by greenestamps(13334) About Me  (Show Source):
You can put this solution on YOUR website!


A great many students find it easy to use the formula for finding the slope between two points incorrectly, ending up with the wrong slope. That of course makes the rest of their work useless.

I strongly recommend that students have at least a mental picture -- if not a sketch with pencil and paper -- to use for finding the slope.

From (1,4) to (3,-2), you move 2 to the right (from 1 to 3) and 6 down (from 4 to -2). The "run" (change in x) is 2; the "rise" (change in y) is -6. The slope is rise over run = -6/2 = -3.

So the equation is of the form

y+=+-3x%2Bb

To find the constant b, substitute the x and y values of either of the given points.

4+=+-3%281%29%2Bb
4+=+-3%2Bb
7+=+b

The equation of the line containing the two points is

y+=+-3x%2B7

Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
DL the FREE graph software at
www.padowan.dk
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y = -3x + 7 (done by another tutor)
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Using the graph software:
Use Ins, then enter -3x + 7
Pick a color and line width.
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Then plot the 2 points, then see if they are on the equation of the line.