Question 62295
Can you explain what it means to solve a linear system using the graph-and-check method?
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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.
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A simple example:
x + y = 2; and x - y = 4
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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
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Plot these two equations, they should look like this:
{{{ graph( 300, 200, -4, 4, -4, 4, 2-x, x-4) }}}
Note that these appear to intersect at x =3,y =-1
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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
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