Question

18 PTS!! What is the 400th term of the sequence below when using the explicit formula

aₙ=a₁+(n-1)•d?

79, 82, 85, 88,...

A. 1273
B. 1279
C. 1276
D. 1282

Answer 1

`\huge\boxed{\sf a_(400)=1276}`

Explanation:

Sequence:

79, 82, 85, 88, ....

Explicit formula:

`a_n=a_1+(n-1)d`

Where,

• 
  `a_n = a_{400` (the term that is to be found)
• 
  `a_1 = 79` (the first term)
• 
  `n = 400`
• 
  `d = 3` (difference between first and second term)

Put the givens in the above formula

`a_(400)=79 +(400-1)3\\\\a_(400)=79 + 399*3\\\\a_(400)=79+ 1197\\\\a_(400)=1276\\\\\rule[225]{225}{2}`