Question

please answer this question ​

Answer 1

Answer:

can't understand the question....

Answer 2

Answer:

Explanation:

12th term=-13

sum of first 4 terms=24

sum of first 10 terms=?

we have;

general term=a+(n-1)d

or, 12th term=a+(12-1)d

or,-13=a+11d

or,-11d-13=a...................................(i)

similarly;

sum of first n terms=n/2(2a+(n-1)d)

or, sum of first 4 terms=4/2(-22d-26+3d)

or, 24=2*(-19d-26)

or, 24=-38d-52

or, 52+24=-38d

or, 76=-38d

or, d=-2

now; putting the value of d in $eq^{n}$(i),we get

-11*(-2)-13=a

or, 22-13=a

or, a=9

hence; sum of first 10 terms=10/2(2*9+(10-1)-2)

                                              =5*(18+9*(-2))

                                              =5*(18-18)

                                              =5*0

                                              =0...........................

                                      is the required answer;;...........