a: We can quickly find the answer by multiplying 3 by 5, then by adding the quantity of the numbers to 19.
![5(3) + 19](https://img.qammunity.org/2023/formulas/mathematics/middle-school/l7b2z5m47ykz8uzwsqowobza0oscqpy94e.png)
15 + 19 = 34
Therefore, the 10th term in this number sequence is 34.
b: n represents the numbered term of the number sequence.
3 can represent x in the expression we make.
![3x = n](https://img.qammunity.org/2023/formulas/mathematics/middle-school/3j176k4bzjwk0a748zv4y7wam6q674np5y.png)
Therefore, a possible expression for this number sequence is 3x = n.