Prove whether or not the following statements are correct. In case they are correct, show whether they are tight or loose bounds: a) n2+4n=O(0.5n?) b) in 0(n2) c) n2+100n=O(n) d) n3-n-=O(n3) e) n log n: O(n log n) g) 2n+1=0(2n) h) 22n=0(2n) i) 10n-=O(2n2) j) (1.5)n=O(n) k) (0.9)n=0(1)