Algebra-2

Question Analysis
This problem assesses the understanding of Descartes' Rule of Signs to determine the possible number of positive real roots.

Key Concept Explanation
Descartes' Rule of Signs states that the number of positive real roots is equal to the number of sign changes in the sequence of coefficients, or less than that by a multiple of 2.

Step-by-step Solution
1. Identify the sequence of coefficients: 6, -3, 1, -7, 9
2. Count the sign changes...