Determine if the sequence is geometric or arithmetic and find the ratio or difference. - 1, 6, - 36, 216

The sequence is an geometric progression;

Nth=a₁r^ (n-1)

a₁ is the first term=-1

r=ratio=a₂/a₁=6/-1=-6

Nth=-1 (-6^ (n-1)

NTh=an

a₁=-1 (-6⁰) = - 1

a₂=-1 (-6¹) = 6

a₃=-1 (-6²) = - 36

a₄=-1 (-6³) = 216

therefore this serie is rising at an increasing fast speed, it is an geometric progression.