Question

answers plzz..with explanation​

Answer 1

Answer:

Step-by-step explanation:

tn=sn-sn-1

t50=s50-s49

t50=12650-12152

=498

m(a+d(m-1))=n(a+(n-1)d )

ma+m^2d - md = na+n^2d - nd

ma-na=(n^2-m^2)d-(n-m)d

m-n(a)=n-m(n+m-1)d

-a=(n+m-1)d

0=a+(m+n-1)d

therefore m+n term is 0

a1+a5+a10+a15+a20+a24 =225

a+a+4d+a+9d+a+14d+a+19d+a+23d = 225

6a+59d=225    

59d=225-6a

l+l-4d+l-9d+l-14d+l-19d+l-23d=225

6l-59d=225

59d=6l-225

59d=59d

225-6a=6l-225

6a+6l=450

a+l=75

sum of  24 terms is

24/2(75)

12*75

900