WEBVTT

1
00:00:00.000 --> 00:00:04.516
Here is the problem: x plus 14 equals 5x plus 2.

2
00:00:04.966 --> 00:00:09.598
A linear equation in x: isolate x using inverse operations.

3
00:00:10.398 --> 00:00:11.884
Start with the equation.

4
00:00:12.334 --> 00:00:14.911
Subtract 5x from both sides.

5
00:00:15.361 --> 00:00:17.834
Subtract 14 from both sides.

6
00:00:18.284 --> 00:00:21.128
Divide both sides by negative 4.

7
00:00:21.928 --> 00:00:25.539
Now look at the graph of the left side minus the right side.

8
00:00:25.989 --> 00:00:29.727
It crosses zero exactly at the solutions we found.

9
00:00:30.527 --> 00:00:32.907
So the answer is x equals 3.

10
00:00:33.357 --> 00:00:42.749
Doing the same operation to both sides keeps the equation balanced. Undoing addition, then multiplication, leaves x alone.

11
00:00:43.549 --> 00:00:51.096
x equals 3: left side equals 17, right side equals 17, which checks out.