C. I think is the right answer.
Answer:
The zeros are

Step-by-step explanation:
We have been given the equation x^4-6x^2-7x-6=0
Use rational root theorem, we have






Again factor using the rational root test, we get

Using the zero product rule, we have

Therefore, the zeros are

the answer for this question is 249,842
Answer:
II) 78
Step-by-step explanation:
2x - 6 + 7x + 15 = 90
9x + 9 = 90
9x = 81
x = 9
<ABC:
7x + 15
7(9) + 15
78