Question

Find the first four terms of this geometric sequence for a1=3 and r=-3

Answer 1

$a_1=3;\ r=-3\\\\a_2=a_1r\to a_2=3\cdot(-3)=-9\\\\a_3=a_2r\to a_3=-9\cdot(-3)=27\\\\a_4=a_3r\to a_4=27\cdot(-3)=-81\\\\Answer:\{3;-9;\ 27;-81\}$