Question

in AP what is the sum of 8,-6,-4........+40 plz ans​

Answer 1

Answer:

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-8.-6,, -4 ,..40

a= -8 d= 2 tn = 40

tn = a+(n-1)d

40= -8 +(n-1) 2

40= -8 + 2n-2

40= -10+2n

2n = 50

n= 25

sn = n/2 ( 2a+ (n-1) d )

= 25/2 ( -16+ 48 )

= 25/2 ( 32 )

= 25x16

= 400

total sum= 400

HOPE IT HELPS U

Answer 2

Given,

a = -8 , l = 40 , d = 2

To find ,

Sn

Solution:

n = [(l - a) ÷ d] + 1

= [(40+8)÷2]+1

= [ 48÷2]+1

=24+1

n = 25

Sn=n÷2(a+l)

=25÷2(32)

= 25×16

=400

Answer:400