Chapter 5 - Exponents and Polynomials - 5.1 - Addition and Subtraction of Polynomials - Problem Set 5.1 - Page 194: 18

$-x^2-x+3$

RECALL: The distributive property states that for any real numbers a, b, and c: $ac+bc= (a+b)c$ Add the polynomials by regrouping the terms and then combining like terms using the distributive property to obtain: $(x^2-2x-1)+(-2x^2+x+4) \\= (x^2-2x^2)+(-2x+x)+(-1+4) \\=(1-2)x^2 + (-2+1)x+3 \\=-x^2+(-x)+3 \\=-x^2-x+3$