Question

A line that includes the points ( - 2, - 9) and ( - 6,n) has a slope of - 1. What is the value of n?

Answer 1

Write out the slope formula:

m = (change in y) / (change in x)

Here,

m = n-(-9) / (-6-(-2)) = (n+9 / (-4)

Now set this slope equal to -1 and solve the resulting equation for n:

(n+9) / (-4) = - 1, or   (n+9) / 4 = 1, or n+9 = 4.  Then n = -5.