Question 57431
solve the system by graphing
L1) x-y=2
L2) 3x-3y=6
For L1) let x=0 and solve for y
0-y=2
-y=2
-(-y)=-(2)
y=-2
Plot (0,-2)
Then let y=0 and solve for x
x-0=2
x=2
Plot (2,0)
Connect the points and you have a line.
:
For L2) let x=0 and solve for y
3(0)-3y=6
-3t=6
-3y/-3=6/-3
y=-2
Plot (0,-2)
Then let y=0 and solve for x
3x-3(0)=6
3x=6
3x/3=6/3
x=2
Plot (2,0), connect the dots and you have a line.
Did you notice that they have the same two points in common?  This is graphically the same line.  That's why you can't see the difference when you've been graphing them.
The solution for this system is all real numbers because they have all points in common.
Here's the graph, one of the line is red, the other is green.
{{{graph(300,200,-10,10,-10,10,-(-x+2),(-3x+6)/-3)}}}
Happy Calculating!!!