Question

a line perpendicular to y=1/4x+3 passes through the point (0,6). Which other point lies on the line

Answer 1

A line perpendicular to y = (1/4)x+3 will have slope -4. 
This is because when you multiply the slopes of the original line and the perpendicular line, you get -1. (1/4)(-4)=-1 
The equation of the perpendicular line is 
y=-4x+b 
This line pases through (0,6) 
6=-4(0)+b 
b=6 
y=-4x+6 is the line