1)An algorithm with best case runtime T(N)=7N+36 and worst case runtime T(N)=3N^2+10N+17, has a lower bound f(N)=7N and an upper bound f(N)=30N^2. These lower and upper bounds provide a general picture of the runtime, while using simpler functions than the exact runtime.

2)Suppose an algorithm's best case runtime complexity is T(N)=3N+6, and the algorithm's worst case runtime is T(N)=5N^2+7N.

ans 12n^2 worst case

Can you please explain why the upper upper bound is 30n^2 (for problem 1) and why it is 12n^2( for problem 2)

i need help understanding

thankyou.