Drawing a Line, Given the Slope and One Point

Date: 05/23/2002 at 16:36:56
From: Karen
Subject: Slope of line with with unknown point

Q: Sketch the line with the given slope through the given point.

How do I draw a line on a graph when I know the slope and only 
one coordinate on the plane?

I tried to use the formula 

  M= (Y2-Y1)/(X2-X1)

I am trying to solve:

  point = (2,1), slope = 2  

Thanks so much for your help.  Everyone in my class needs it.
:-)

Date: 05/25/2002 at 11:28:23
From: Doctor Ian
Subject: Re: Slope of line with with unknown point

Hi Karen,

Start by plotting the point you know:

  |
  -
  |
  -      *
  |      
  +--|---|--

Then think about what the slope tells you.  It tells you that 
rise/run is 2, which means that if you move two units up, and one 
to the right, you'll still be on the line:

  |
  -      ....* (2+2,1+1)
  |      .
  -      .
  |      .
  -      *  (2,1)
  |      
  +--|---|---|---|---
  
And now you have _two_ points on the line.  Can you take it from 
here? 

- Doctor Ian, The Math Forum
  http://mathforum.org/dr.math/ 

Date: 05/30/2002 at 15:44:01
From: Karen
Subject: Slope of line with with unknown point

Thank you Dr. Ian!

I'll share your solution with all of my friends in class.

Karen