Question 110440
Y=-3X+1 (RED LINE)HAS A SLOPE OF -3 & A Y INTERCEPT OF 1.
FOR A PERPENDICULAR LINE TO THIS LINE IT HAS TO HAVE A SLOPE=1/3.
NOW REPLACE THE X & Y VALUES IN THE LINE EQUATION[Y=mX+b] WITH THE SLOPE OF 1/3 & THE (X,Y) VALUES (0,5) & SOLVE FOR THE Y INTERCEPT.
5=1/3*0+b
b=5 
SO WE HAVE THE LINE EQUATION WITH A SLOPE OF 1/3 & PASSING THROUGH(0,5):
Y=X/3+5 (GREEN LINE)
{{{ graph( 300, 200, -16, 5, -6, 10, y = -3x +1, y = x/3 +5) }}} (graph 300x200 pixels, x from -16 to 5, y from -6 to 10, of TWO functions y = -3x +1 and y = x/3 +5).