The equation of the line

Question

Find an equation for the line which passes through (-1,3) and is perpendicular to the line containing  (0,4) and (3,7) in slope intercept form.

Answer 1

First, find the slope.

 

(7 - 4)/(3 - 0) = 3/3 = 1

 

Perpendicular lines have opposite, reciprocal slopes. The opposite reciprocal of 1/1 is -1/1, which we call -1.

 

Now, point slope form.

 

y - 3 = -1(x - (-1))

y - 3 = -x - 1

y = -x + 2