theta notation

Which of the following can be recurrence relation(s) corresponding to an algorithm with time complexity $\Theta(n)$ ?

Let $T(n)$ be the recurrence relation defined as follows: $T(0) = 1$ $T(1) = 2$, and $T(n) = 5T(n - 1) - 6T(n - 2)$ for $n \geq 2$ Which one of the following statements is TRUE?

Consider the following function: int unknown(int n) { int i, j, k = 0; for (i = n/2; i <= n; i++) for (j = 2; j <= n; j = j * 2) k = k + n/2; return k; } The return value of the fu...