Question 214236
Y=mX+b
-2=1*4+b
-2=4+b
b=-2-4
b=-6 the y intercept.
y=x-6
{{{ graph( 300, 200, -6, 7, -10, 10, x -6) }}} (graph 300x200 pixels, x from -6 to 7, y from -10 to 10, x -6).
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No slope:
y=-6 
{{{ graph( 300, 200, -6, 7, -10, 10, y = -6) }}} (graph 300x200 pixels, x from -6 to 7, y from -10 to 10, y = -6).
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(3,-3) slope=2 
-3=-2*3+b
-3=-6+b
b=-3+6
b=3 y intercept.
y=2x+3 (red line)
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Perpendicular line through (4,4)
Perpendicular line will have a slope=-1/2
4=-1/2*4+b
4=-2+b
b=4+2
b=6
y=-x/2+6 (green line)
{{{ graph( 300, 300, -6, 10, -6, 10, 2x +3, -x/2 +6 ) }}} (graph 300x300 pixels, x from -6 to 10, y from -6 to 10, of TWO functions 2x +3 and -x/2 +6).