Algebra: Chapter 5, Lesson 8, page 236.
Subtraction of Polynomials
We do just like the addition of polynomials, except for subtraction, we (remember way back to subtracting with negative numbers) add the opposite. The other thing we have to remember is the sign problems for double negatives, make “Change-change” or “bling-bling” with 2 negatives
You can do the subtraction horizontally or vertically. Horizontally requires that you scan across the polynomials. It’s easier for me to put the polynomials in descending order and then combine like terms, remembering the combining terms MUST HAVE THE SAME VARIABLE AND THE SAME EXPONENTS!
If you do the problems horizontally, remember that the `-` sign turns everything in 2nd polynomial’s parenthesis `( x^2 …)` to its opposite sign!
Vertically (or columns in the textbook) require you to write out the problem with spaces for missing terms. It is easier to line up terms this way and you can stick in other terms as well that are not common to both polynomials.
See here for more examples too.