Question

What is the nth term of the arithmetic sequence 121,99,77,55?

Answer 1

143 - 22n

Explanation:

For the standard Arithmetic sequence.

a,a+d,a+2d,a+3d,............. , a+(n-1)d

a is the first term ,d, the common difference and

`color(red)(|bar(ul(color(white)(a/a)color(black)( a + (n-1)d)" the nth term "color(white)(a/a)|)))`

here a = 121 and d = 99-121 =77-99 = -22

hence nth term = 121 -22(n - 1) = 121 -22n + 22 = 143 - 22n