Answer: The first four terms of the given geometric sequence are 3, -9, 27 and -81.
Step-by-step explanation: We are given to find the first four terms of the geometric sequence, where
first term is 3 and common ratio is -3.
That is

We know that
the n-th term of a geometric series with first term a and common ratio r is given by

Therefore, the first four terms are

Thus, the first four terms of the given geometric sequence are 3, -9, 27 and -81.