The given recurrence relation is:

$u_1 = 3, \quad u_n = 3 \times u_{n-1} - 4, \quad n \geq 2$

We will compute the first four terms $u_1, u_2, u_3, u_4$.

1. $u_1 = 3$ (given)
2. For $u_2$: $u_2 = 3 \times u_1 - 4 = 3 \times 3 - 4 = 9 - 4 = 5$
3. For $u_3$: $u_3 = 3 \times u_2 - 4 = 3 \times 5 - 4 = 15 - 4 = 11$
4. For $u_4$: $u_4 = 3 \times u_3 - 4 = 3 \times 11 - 4 = 33 - 4 = 29$

Thus, the first four terms are:

$u_1 = 3, \quad u_2 = 5, \quad u_3 = 11, \quad u_4 = 29$

Would you like more details or have any questions?

Here are 5 related questions you might consider:

1. What is the general form of the $n$-th term of this sequence?
2. Can we express this recurrence relation explicitly without recursion?
3. How does the growth rate of this sequence compare to a geometric sequence?
4. How would you modify the recurrence relation to generate a decreasing sequence?
5. What happens to the sequence as $n$ approaches infinity?

Tip: Recurrence relations often reveal interesting long-term behavior, so analyzing them for limits or patterns can provide deeper insights.