34. Series with repetitions. What is the $n$-th term of the series

$$
-4+7-4+7-4+7-\ldots ?
$$
34. Subtracting $\frac{1}{2}(7-4)=1.5$ from each term of the series

$$
-4+7-4+7-4+7 \ldots
$$

we get

$$
-5.5+5.5-5.5+5.5-5.5+5.5-\ldots
$$

Therefore, the $n$-th term of the series is $1.5+5.5(-1)^{n}$.