write down in term of n an expression for the n th term of the following sequence a) 4,1,-2,-5,-8. b) - 7,-12,-17,-22,-27

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