Answer:
The answer to your question is: -3 and 7
Explanation:
To know if a value is a zero of the polynomial is necessary to find the prime factors of 84.
84 2
42 2
21 3
7 7
1
Then, the possible values are ±1, ±2, ±3, ±7.
After that, we evaluate each value in the polynomial, if the result is zero, that number is a root of the polynomial.
Example
(-3)³ - 8(-3)² - 5(-3) + 84
-27 - 72 + 15 + 84
- 99 + 99 = 0
Then, -3 is a zero of the polynomial
(7)³ - 8(7)² - 5(7) + 84
343 - 392 - 35 + 84
427 - 427 = 0
Then, 7 is a zero of the polynomial