Question

9+7+5+3....... to 14th term

Answer 1

Answer:

Step-by-step explanation:

given

,n=14;a=9; d=7-9=-2

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

therefore,

S14=14/2(2(9)+(14-1)(-2))

. =14(9-13)

. =14(-4) =-56

therefore the answer is -56

hope my answer is useful to you. feeling nice to helping you.

Answer 2

Step-by-step explanation:

a=9 , a+d=7

therefore,d=7-9=(-2)

[n=14,a=9,d=(-2)]

sum of 14 terms=[(n/2)×{(2a)+(n-1)d}]

=[(14/2)×{(2)(9)+(14-1)(-2)}]

=[(7)×{(18)+(13)(-2)}]

=[(7)×{(18)-(26)}]

=[(7)×(-8)]

=-56