Question

Find the sum of first 22 terms of AP; 8, 3, -2........................​

Answer 1

Answer:--979

Step-by-step explanation:

The AP is 8,3,-2..........an

A1=8. d=-5. n=22

S22=n/2{2a+(n-1)d

=22/2{2(8)+21(-5)

= 11{16+(-105)}

=11×(-89)

=-979

Answer 2

Here is the answer to your question!!

Solution :

Here, a= 8, d= 3-8 = -5, n= 22

We know,

$\: S = \frac{n}{2} \: [ 2a + (n - 1)d \: ] \\ \\ </strong></p><p></p><p><strong>[tex] \: S = \frac{n}{2} \: [ 2a + (n - 1)d \: ] \\ \\ \: S = \frac{22}{2} \: \: [ 2 \times 8 + (22 - 1)d \: ] \\ \\ \ \\ S \: = 11(16 - 105) \\ \\ = \: S = 11 \times - 89 \\ \\ \: S = - 979 \\ \\ \\ \\ \\ \: So \: \: the \: \: sum \: \: of \: first \: \: 22 \: \: terms \: \: of \: \: \: AP \: \: is \: \: - 979.$

Hope it helped!!