SOLUTION: Can you explain what it means to solve a linear system using the graph-and-check method?

Algebra ->  Coordinate Systems and Linear Equations  -> Lessons -> SOLUTION: Can you explain what it means to solve a linear system using the graph-and-check method?      Log On


   



Question 62295This question is from textbook Algebra 1: Concepts and Skills
: Can you explain what it means to solve a linear system using the graph-and-check method? This question is from textbook Algebra 1: Concepts and Skills

Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
Can you explain what it means to solve a linear system using the graph-and-check method?
:
What I think it means is you plot the two equations, note the x,y coordinates
where they intersect. Substitute these values in the original equations to see
if they are correct.
:
A simple example:
x + y = 2; and x - y = 4
:
Arrange equations to the general form "y="
x + y = 2:
y = 2 - x;
and
x - y = 4
-y = 4 - x
Get rid of the neg y, mult eq by -1:
y = x - 4
:
Plot these two equations, they should look like this:
+graph%28+300%2C+200%2C+-4%2C+4%2C+-4%2C+4%2C+2-x%2C+x-4%29+
Note that these appear to intersect at x =3,y =-1
:
Substitute these value in the original equations:
x + y = 2
3 - 1 = 2, correct
and
x - y = 4
3 - (-1) = 4,
3 + 1 = 4, remember a minus a minus is a plus
: