Pre-Calculus Courses
University of California, Irvine via Coursera Pre-Calculus
Universitat Autònoma de Barcelona (Autonomous University of Barcelona) via Coursera Pre-Calculus: Functions
University of California, Irvine via Coursera Calculus 1: The Complete Guide
Udemy Perfect Your Mathematical Skills (Pre-Calculus Course)
Udemy Absolute Value Equations and Inequalities
Udemy Pre-Calculus
Brilliant Graphing the Trigonometric Functions
patrickJMT via YouTube Pre Calc Topics
statisticsmatt via YouTube Transitioning to Calculus
YouTube