WEBVTT

1
00:00:00.000 --> 00:00:07.233
Here is the problem: Find the slope and equation of the line through (negative 4, 5) and (2, negative 7).

2
00:00:07.683 --> 00:00:11.329
Find the slope (rate of change) of the line through two points.

3
00:00:12.129 --> 00:00:13.209
Label the points.

4
00:00:13.659 --> 00:00:15.667
Find the change in y (rise).

5
00:00:16.118 --> 00:00:17.894
Find the change in x (run).

6
00:00:18.344 --> 00:00:19.865
Divide rise by run.

7
00:00:20.665 --> 00:00:23.579
Find the y-intercept using the first point.

8
00:00:24.029 --> 00:00:25.689
Write the equation of the line.

9
00:00:26.489 --> 00:00:31.992
So the answer is m equals negative 2; y equals negative 2x minus 3.

10
00:00:32.442 --> 00:00:40.615
The slope is negative 2: for every 1 unit increase in x, y changes by negative 2. The line falls from left to right.

11
00:00:41.415 --> 00:00:48.404
Second point: negative 2 times (2) plus negative 3 equals negative 7 (expected negative 7).