use formula from 2c to find the values of t and t

Question

7 20

c)36,31,25,21,...

Answer 1

I don't understand it . could you work this one for me .

Answer 2

(a) do not know the formula
(b) your text formatting sucks. try writing fractions as 3/4 and sequence terms as t7 or t20

Answer 3

thank you Steve