WEBVTT

1
00:00:00.000 --> 00:00:06.954
Here is the problem: Find the slope and equation of the line through (negative 1, 4) and (3, negative 2).

2
00:00:07.404 --> 00:00:11.084
Find the slope (rate of change) of the line through two points.

3
00:00:11.884 --> 00:00:13.010
Label the points.

4
00:00:13.460 --> 00:00:15.411
Find the change in y (rise).

5
00:00:15.861 --> 00:00:17.521
Find the change in x (run).

6
00:00:17.971 --> 00:00:19.538
Divide rise by run.

7
00:00:20.338 --> 00:00:23.322
Find the y-intercept using the first point.

8
00:00:23.772 --> 00:00:25.432
Write the equation of the line.

9
00:00:26.232 --> 00:00:33.291
So the answer is m equals negative 3 over 2; y equals (negative 3 over 2)x plus 5 over 2.

10
00:00:33.741 --> 00:00:43.133
The slope is negative 3 over 2: for every 1 unit increase in x, y changes by negative 3 over 2. The line falls from left to right.

11
00:00:43.933 --> 00:00:51.015
Second point: negative 3 over 2 times (3) plus 5 over 2 equals negative 2 (expected negative 2).