You can put this solution on YOUR website!
through(4,7) perpendicular to the line that passes through (3,6) and (3,15)
SLOPE=(15-6)/(3-3)=9/0 THIS INDICATES A VERTICLE LINE THROUGH X=3 (red line)
THE PERPENDICULAR LINE WOULD HAVE A SLOPE=0.
Thus the equation for this perpendicular line is:
y=7 (green line)
(graph 300x200 pixels, x from -6 to 5, y from -10 to 10, of TWO functions x = 3 and y = 7).