Question

2+6+10................................+38=?
solve with specific formula.
Thanks,​​

Answer 1

Step-by-step explanation:

a=2

d=4

tn=38

tn=a+(n-1)d

38=2+4n-4

40=4n

n=10

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

S10=5{4+36}

=5x40

=200

Answer 2

Step-by-step explanation:

l = a+(n-1)d = 38

here a = 2 and d = 4

(n-1)4 = 36

n= 9+1

n= 10

Sn = n/2[a+l]

$n = 5 × 40

200