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Lesson: Descartes's Rule of Signs

In this lesson, we will learn how to use Descartes’s rule of signs to get all possible numbers of positive and negative real roots.

Sample Question Videos

Worksheet • 3 Questions • 1 Video

Q1:

Using Descartes’s rule of signs, find which of the following describes the possible real zeros of .

A has either 2 or 0 positive zeros and either 3 or 1 negative zeros.
B has either 3 or 1 positive zeros and either 2 or 0 negative zeros.
C has 0 positive zeros and either 3 or 1 negative zeros.
D has either 3 or 1 positive zeros and 0 negative zeros.
E has either 2 or 0 positive zeros and 1 negative zero.

Q2:

Using Descartes’s rule of signs, find which of the following describes the possible real zeros of .

A has either 2 or 0 positive zeros and one negative zero.
B has either 3 or 1 positive zeros and 0 negative zeros.
C has 1 positive zero and 0 negative zeros.
D has 1 positive zero and either 2 or 0 negative zeros.
E has 0 positive zeros and either 3 or 1 negative zeros.

Q3:

Using Descartes’s rule of signs, find which of the following describes the possible real zeros of .

A has either 2 or 0 positive zeros and either 2 or 0 negative zeros.
B has 1 positive zero and either 3 or 1 negative zeros.
C has either 2 or 0 positive zeros and 0 negative zeros.
D has either 3 or 1 positive zeros and 1 negative zero.
E has 0 positive zeros and either 2 or 0 negative zeros.

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