Optional:
Here is a prove that product of the slopes of two perpendicular lines is -1 by using the knowledge you have learned.
https://www.youtube.com/watch?v=DAeXPJ3Jd2Y
Here is a prove that product of the slopes of two perpendicular lines is -1 by using the knowledge you have learned.
https://www.youtube.com/watch?v=DAeXPJ3Jd2Y