Which graph represents the sequence: 80, - 40, 20

80/-40=-40/20=-2,

the sequence: 80, - 40, 20 is a geometric sequence

its general formula is Vn+1 = q Vn, where q = - 2,

if we put Vn+1 = f (x)

Vn = x

so we have f (x) = - 2x so the graph that represents the sequence is graph of linear equation