Question 179891
1.{{{y=5x+2}}}
2.{{{y=5x+9}}}
3.{{{y=-5x+2}}}
4.{{{y=5x-4}}}
Lines 1,2, and 4 (red, green, and purple) are parallel to each other because they have the same slope (5) and different y-intercepts. Line 3 (blue) is neither parallel nor perpendicular to the other lines.
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 {{{ graph( 300,300, -5, 5, -5, 5, 
5x+2,
5x+9,
-5x+2,
5x-4) }}}