Question 229346
LINES ARE PARALLEL IF THEIR SLOPES ARE EQUAL.
EXAMPLE:
Y=3X/5+3 (RED LINE)
Y=3X/5-4 (GREEN LINE)
{{{ graph( 300, 200, -6, 5, -10, 10, 3x/5 +3, 3x/5 -4) }}} (graph 300x200 pixels, x from -6 to 5, y from -10 to 10, of TWO functions 3x/5 +3 and 3x/5 -4).