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How do you find the slope of a line? Like what is the equation for it?   Here is and example  

 Jul 13, 2014

Best Answer 

 #1
avatar+124676 
+10

There is a "formula" for calculating the slope.

m = (y2 - y1) ' (x2 - x1)   where m is the slope.

Basically, it says to subtract the y values in some order and then subtract the x values in the same order.  Then, put the first result over the second to get the slope.

OK......let's subtact the y's in this order   ...    5 - (-1)  = 6

And now we'll subtract the x's in the same order  ....   -2 - 0  = -2

Now.....put the first thing over the second......    6/-2 = -3

And there's the slope. This says that everytime x chages by 1, y changes by -3. Look at the graph to verify this for yourself.

Let me emphasize one thing.....the order of subtraction must remain the same between the  y's and the x's, or else your answer will be incorrect. Note, if the line "falls" from left to right and we get a positive slope.......we've done something wrong!! The slope should be negative in this situation!!! This is always a good visual check to ensure that our answer makes sense.

 

 Jul 13, 2014
 #1
avatar+124676 
+10
Best Answer

There is a "formula" for calculating the slope.

m = (y2 - y1) ' (x2 - x1)   where m is the slope.

Basically, it says to subtract the y values in some order and then subtract the x values in the same order.  Then, put the first result over the second to get the slope.

OK......let's subtact the y's in this order   ...    5 - (-1)  = 6

And now we'll subtract the x's in the same order  ....   -2 - 0  = -2

Now.....put the first thing over the second......    6/-2 = -3

And there's the slope. This says that everytime x chages by 1, y changes by -3. Look at the graph to verify this for yourself.

Let me emphasize one thing.....the order of subtraction must remain the same between the  y's and the x's, or else your answer will be incorrect. Note, if the line "falls" from left to right and we get a positive slope.......we've done something wrong!! The slope should be negative in this situation!!! This is always a good visual check to ensure that our answer makes sense.

 

CPhill Jul 13, 2014

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