QuestionWhat are the first three terms of the geometric sequence $a_{n}=-7 \cdot 3^{n-1}$ ? $$\begin{array}{l} a_{1}=\operatorname{Ex} 123 \hat{2} \\ a_{2}=\operatorname{Ex} 123 \hat{2} \\ a_{3}=E x \cdot 123 \hat{2} \end{array}$$

Studdy Solution
To find the third term $a_3$, substitute $n = 3$ into the formula for the sequence:
$$a_3 = -7 \cdot 3^{3-1}$$ $$a_3 = -7 \cdot 3^2$$ $$a_3 = -7 \cdot 9$$ $$a_3 = -63$$
The first three terms of the geometric sequence are:
$$a_1 = -7, \quad a_2 = -21, \quad a_3 = -63$$