Learn how to add and subtract polynomials. For example, how do you add (-5x2 + 12x ) + ( 2x2 - 18x ) Follow these steps. Remove the parenthesis by distributing the addition or subtraction sign. Combine like Terms Place in descending order. This video is part of my Algebra 1 course. This playlist has all of the videos completed so far. Algebra 1 Playlist