Question 49731
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Please...I need help solving the following 
system by graphing

 x - 2y =  8
3x - 2y = 12

1.  Find the x-intercept of the first equation,
    by substituting y = 0 and solving for x

      x - 2y = 8
    x - 2(0) = 8
           x = 8
         
    So the x-intercept is the point (8,0) on 
    the x-axis


2.  Find the y-intercept of the first equation, 
    by substituting
    x = 0 and solving for y

    x - 2y = 8
    0 - 2y = 8
       -2y = 8
         y = -4

    So the y-intercept is the point (0, -4) on 
    the y-axis.

Plot these two points and draw a line through them.

{{{ graph( 300, 300, -3, 10, -10, 3, (8-x)/(-2)) }}}

3.  Find the x-intercept of the second equation, 
    by substituting y = 0 and solving for x

        3x - 2y = 12
      3x - 2(0) = 12
             3x = 12
              x = 4 
         
    So the x-intercept is the point (4,0) on the 
    x-axis

4.  Find the y-intercept of the second equation, 
    by substituting x = 0 and solving for x

      3x - 2y = 12
    3(0) - 2y = 12
          -2y = 12
            y = -6

    So the y-intercept is the point (0, -6) on the 
    y-axis.

Plot these two points and draw a line through them 
on the same set of axes.

{{{ graph( 300, 300, -3, 10, -10, 3, (8-x)/(-2), (12-3x)/(-2)) }}}

Now look and see what the coordinates are of the point
where the two lines cross:

You will notice that point is directly under 2 on the 
x-axis, and it's directly to the right of -3 on the
y-axis.  So the solution of the system is

(x,y) = (2,-3)  

We can check that to see if it is correct. Substitute
x=2 and y=-3 into both of the original equations and
see if you end up with the same number on both sides.

     x - 2y = 8                 3x - 2y = 12
(2) - 2(-3) = 8            3(2) - 2(-3) = 12
      2 + 6 = 8                   6 + 6 = 12 
          8 = 8                      12 = 12

It checks in both. 

Edwin</pre></font></b>