Question

find the sum of given below(ii) -5 +(-8)+(-11)+...+(-230)​

Answer 1

Step-by-step explanation:

-5+(-8)+(-11)+..+(-230)

this is A. p.

here

a=-5

d=-3

an=-230

so

sum of this series

sn=n/2(a+an)

we need to find n here

so

an=a+(n-1) d

-230=-5+(n-1) (-3)

-230=-5-3n+3

-230=-2-3n

3n=-2+230

3n=228

n=76

now

sn=76/2(-5-230)

sn=36(-235)

sn=-8460

-8460 is the answer

hope you understand

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Answer 2

Answer:

DATA

a=-5

d=-8-(-5)=-3

an(l)=-230

an=a+(n-1)d

-230=-5+(n-1)-3

-230+5=-3n+3

-225=-3n+3

-225-3=-3n

-228=-3n

n=-228/-3

n=76

sn=n/2(a+l)

sn=76/2(-5-230)

sn=38(-235)

sn=-8930