Question 55464
<pre><font size = 5 color = "darkblue"><b>write the general equation form of the line 
which passes through the 2 points: (1,2), (6,7)

You need two formulas:

     y<sub>2</sub> - y<sub>1</sub>
m = --------- to find the slope, m, and
     x<sub>2</sub> - x<sub>1</sub>

then you substitute the value you get for m, then 
substitute the values for x<sub>1</sub> and y<sub>1</sub>. Do not
substitute anything for x and y.  Just leave them
variable:

y - y<sub>1</sub> = m(x - x<sub>1</sub>)

(x<sub>1</sub>,y<sub>1</sub>) = (1,2), (x<sub>2</sub>, y<sub>2</sub>) = (6,7)

so

     y<sub>2</sub> - y<sub>1</sub>     7 - 2     5
m = --------- = ------- = --- = 1
     x<sub>2</sub> - x<sub>1</sub>     6 - 1     5

Then 

y - y<sub>1</sub> = m(x - x<sub>1</sub>) becomes

 y - 2 = 1(x - 1)

 y - 2 = x - 1
   + 2     + 2
 -------------
 y     = x + 1

That's the equation:

     y = x + 1

Edwin</pre>