4.6.4 Using Descartes' Rule of Signs

Question 1

Descartes’ rule of signs informs us about potential roots

Answer 1

1. Write the polynomial with the highest degree term first and the others following in descending order.
2. Next, examine the function when +x is substituted. The number of sign changes from one term to the next tells you the
   number of positive real roots or that number less some real even number.
3. Finally, look at the function when –x is substituted. The number of sign changes from one term to the next now tells
   you the number of negative real roots or that number less some real even number.