Answer:
answer of your question is
-x= -7
The answer would be (The two ranges are close together, so there are probably no outliers in this set. )
C
Using Descartes' rule of signs
look for the number of sign changes in f(x)
+ / + / - / -
There is 1 sign change hence 1 positive zero
f(-x) = -x³ + x² + 8x - 8
look for the number of sign changes in f(- x)
- / + / + / -
there are 2 sign changes hence 2 possible negative zeros
Answer:
Final answer iis choice B) 
Step-by-step explanation:


Compare with quadratic equation
, we get:
a=2, b=3, c=8
Now plug these values into quadratic formula:




Hence final answer iis choice B) 