00:01
Okay, so what exactly is slope -intercept form? well, this is when a linear equation or a line is written as y equals mx plus b, where m represents my slope and b is my y -intercept, or where i cross the y -axis.
00:18
To get to slope -intercept form, all i have to do is get y by itself on one side of the equation.
00:26
So x minus four y equals 20.
00:28
I wanna get y by itself, so what am i gonna move? let's move over x.
00:32
I'm adding x, opposite of adding, let's subtract.
00:36
Negative four y equals negative x plus 20, okay? is y by itself? no, it has a negative four attached, specifically multiplied.
00:46
Opposite of multiplied is divide, and i have to divide to each term.
00:52
This gives me y, negative over negative is positive 1 4th x.
00:56
20 divided by negative four is negative five.
00:59
Okay, so what do i care about? well, i'm trying to determine if it's perpendicular.
01:04
So perpendicular lines cross at a nine degree angle, and how do i know if they're perpendicular? well, the slopes are opposite reciprocal...