Question

Find the 8th term of the arithmetic sequence - 2x + 7,4x + 1, 10x – 5, ...

Answer 1

Explanation:

a1 = -2x + 7

d = 4x + 1 - (-2x + 7)

d = 4x + 1 + 2x - 7

d = 6x - 6

n = 8

a8 = -2x + 7 + (n-1)*d

a8 = -2x + 7 + (8 -1 ) * (6x - 6)

a8 = -2x + 7 + 7 * (6x - 6)

a8 = -2x + 7 + 42x - 42

a8 = 40x - 35