Question 30150
The y-intercept means "where am I on the y-axis when x=0?"
So make x=0 and whatever y is, that's the y-intercept.
 A line with slope = m is perpendicular to what ever line has 
the slope -1/m
  say the equation is the most simple one
{{{y = x}}}
The y-intercept is whatever I get when x = 0.
{{{y = 0}}} that's the y-intercept
What's the line perpendicular to {{{y=x}}}?
{{{y = mx + b}}} is the general slope-intercept formula
How does it compare with {{{y = x}}}?
{{{y = 1*x + 0}}}
So 1 is the slope
any line perpendicular to it will have slope -1/m or -1/1
which is -1
Hope all this makes sense. Keep working at it.