Question 121474
find the slope (-2-10)/(3-9)=-12/6=-2 this is the slope
Y=mX+b
10=-2*9+b
b=10+18
b=28 THUS THE EQUATION OF THIS LINE IS:
Y=-2X+28 (RED LINE)
THIS LINE HAS AN X INTERECEPT OF:
0=-2X+28
-2X=-28
X=-28/-2
X=14 OR (14,0) 
THE LINE PERPENDICULAR WOULD HAVE A SLOPE=1/2 PASSING THROUGH (12,0)IS:
0=1/2*12+b
b=-6 
Y=X/2-6 IS THE EQUATION OF THIS PERPENDICULAR LINE PASSING THROUGH (12,0) OR THE (GREEN LINE)
{{{ graph( 300, 300, -6, 15, -10, 30, y = -2x +28, y = x/2 -6) }}} (graph 300x300 pixels, x from -6 to 15, y from -10 to 30, of TWO functions y = -2x +28 and y = x/2 -6).