Find the sum of the geometric sequence –3, 15, –75, 375, … when there are 7 terms and select the correct answer below

Hello here is a solution :

“exterior angles of triangles. an exterior (or external) angle is the angle between one side of a triangle and the extension of an adjacent side. try this drag the orange dots on any vertex to reshape the triangle.” look to get to the answer i explained what it means and other things i hope it you .