Answer:
1/2
Step-by-step explanation:
The Rational Root Theorem says that any rational root has
1. a numerator that is a factor of the constant term
2. a denominator that is a factor of the leading coefficient (that's attached to the highest-power term)
Numerator: [tex]\pm 1[/tex]
Denominator: [tex]\pm 2[/tex]
That means there are only two possible rational roots: [tex]\pm \frac{1}{2}[/tex]
Try them both by plugging them into the polynomial.
[tex]2\left(\frac{1}{2}\right)^3 + 3\left(\frac{1}{2}\right)^2 -1= \frac{1}{4}+\frac{3}{4}-1 =0[/tex]
Aha! The negative one-half value does not produce 0