Answer:
(a) O(x²)
(b) O(x²)
(c) O(x²)
(d) Not O(x²)
Step-by-step explanation:
If a function is O(x²), then the highest power of x in the function ia greater or equal to 2.
(a) 100x + 1000
This is O(x), not O(x²)
(b) 100x² + 1000
This is O(x²)
(c) x³.100 − 1000x²
This is O(x²)
(d) x log x²
This is not O(x²)