Adding and subtracting polynomials

Adding or subtracting polynomials gives a polynomial again. To find a sum, we write the polynomials in brackets, remove the brackets (with a plus before a bracket the signs stay) and combine like terms. In a difference there is a minus before the bracket, so every term of the subtrahend changes its sign: (5a - 2b) - (3a - 4b + 1) = 5a - 2b - 3a + 4b - 1 = 2a + 2b - 1. Polynomials can also be added by the “column” method: like terms are written under each other and combined column by column. We write the result in standard form. The most common mistake in subtraction is forgetting to change the signs of the terms of the second polynomial.