Respuesta :

u have an arithmetic sequence.....an = a1 + (n - 1) * d

an = a1 + (n - 1) * d
a1 = first term = 3
n = term to find
d = common difference = -4

so basically, ur adding -4 to each term to get to the next one
starting at 3....
3 - 4 = -1
-1 - 4 = -5
-5 - 4 = -9

so ur sequence is { 3,-1,-5,-9 }