202k views
2 votes
What is the equation of the line that contains the points (-1,1) & (-3,3)

User Shaheeda
by
4.6k points

1 Answer

7 votes

A = (-1, 1)

B = (-3, 3)

slope = 3 - 1 / -3 - (-1)

slope = 2 / -2

slope = -1

Lets apply the point slope line equation:

y - yo = m(x - xo)

where

(xo, yo) is a point that lies in the line

m = slope

We can use any of the two points to calculate the equation. I'm going to choose (-1, 1). We have:

y - yo = m(x - xo)

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

y - 1 = -1(x + 1)

y - 1 = -x - 1

y = -x -1 + 1

y = -x

or

-x + y = 0

Answer: the equation of that line is y = -x or -x + y = 0

User Aimiliano
by
4.7k points