What is the common difference of the arithmetic sequence below?

17, -3, -23, -43, ...

What would be the next three terms in the sequence 2.9, 3.2, 3.5, 3.8, ...

(separate with commas)

Find a₃ in a sequence with a₁ = 20 and a_n = a_n-1 - 17

Find a₅ in a sequence with a₁ = 2 and a_n = a_n-1 + 0.4

Find the 8th term in a sequence with the explicit formula

a_n = 20 - 17(n - 1)

Find a₂₁ in the sequence with the explicit formula

a_n = 2 + 0.4(n - 1)

The nth term of an arithmetic sequence with common difference d and first term a1 is:

a_n = a₁ + (n-1)d

Find the 22nd term: 5, 2, -1, -4,...

Find the 90th term of this sequence:

12, 8, 4, 0,...

Find the 15th term: a(1) = 7; d = 3