This document discusses adding and subtracting polynomials: - To add polynomials, combine like terms by adding coefficients of the same variables; for example, to add 5x + 7 and 8 - 2x, the terms are 5x + 8 - 2x + 7 = 3x + 15 - To subtract polynomials, change the sign of each term in the polynomial being subtracted and then combine like terms; for example, to subtract 3a + b from 7a + 5b, write 7a + 5b - (-3a - b) = 7a + 5b + 3a + b = 10a + 6b - When combining like terms, collect all terms with the same variables and add their coefficients.