Wednesday, April 27, 2011

April 27, 2011

There are 3 types of lines:

  1. Parallel lines - the slope for each line is the same.  There is no common solution.  "My son and I will never be the same age".  
  2. 1 intersection - intersect at exactly one point.  The lines will never intersect again.  There is 1 common solution.  The point makes the equation for both lines true.  "My dog and I will eventually be at the same age because we age at different rates."
  3. Infinite intersection lines - all intersecting points are common.  "My identical twin and I will always be the same age."
Solving Systems by Graphing:


The lines intersect at (4,10)
The solution to this system is x = 4, y = 10
Another system to solve: 
The lines intersect at (2,4)
Solution to this system is x = 2, y = 10
**Sometimes the systems are not in slope intercept form.  So, in that case you need get it there.**
Example:
  • x + y = 8 and y = 3x
    • x + y = 8 is not in slope intercept form.  Subtract x from both sides.  The equation then turns into: y = -x + 8.  This is now in slope intercept form.
    • The lines intersect (2,6)
      The solution to this system is x = 2, y=6
We used a graphing calculator to solve these problems. We had to find the intersection
and in what quadrant.
#1 is (-1,2) Quadrant 3
#7 is (-1,3) Quadrant 2
#10 is (3,8) Quadrant 1
Free online Graphing Calculator
you can use the above link to solve these problems.

This is a problem we solved, but I used the online graphic calculator 
Another problem that we did.  I did this one on paper, using two different methods.
*The first putting both equations in slope intercept form and them using a graphing
calculator.
*The second, using a T table for each equation and looking for coordinates
that are identical
Write the equations in slope intercept form. 
(don't solve the systems)


No comments: