Question

If the 100th term of an arithmetic sequence is 287, and its common difference is 3, then

its first term a1 = ________
its second term a2 = ________
its third term a3 = _______

Hint: Use an =a1 + (n-1) d

Answer 1

-10

-7

-4

Explanation:

287 =
`a_{1` + (n-1)3

287 =
`a_(1)`+ (100-1)3

287 =
`a_(1)` + 99(3)

287 =
`a_(1)` + 297 Subtract 297 from both sides

-10 =
`a_(1)`

If the first term is -10 The second term is 3 greater -7 and the third terms is 3 greater than that. -4