.Write the nth term of the following sequence in terms of the first term of the sequence.

1, 8, 15, 22, . . .

1 + 7(n - 1)

Write the nth term of the following sequence in terms of the first term of the sequence.

10, 20, 40, . . .

10 * 2^(n - 1)

Write the nth term of the following sequence in terms of the first term of the sequence.

2, -4, 8, -16, . . .

2 * (-2)^(n - 1)