Say you have 2 perpendicular lines that are:
[tex]y=2x+2[/tex]
[tex]y=- \frac{1}{2} -2 [/tex]
These lines are perpendicular because the slope is the negative reciprocal(flip the numerator and denominator EX: [tex] \frac{2}{1}=2 [/tex] therefore the negative reciprocal is [tex]- \frac{1}{2} [/tex]) and the y-intercept is just where each of the lines cross the y-axis.
