Respuesta :

devishri1977

Answer:

Step-by-step explanation:

a) a = 4; d =1-4 = -3

nth term = a + (n-1)*d

              = 4 + (n-1) * -3 = 4 -3n +3

nth term =7 - 3n

b) a = -7; d = -12 - (-7) = -12 + 7 = -5

nth term = -7 + (n-1) * -5

              = -7 - 5n + 5

              = -2 - 5n