Question

the first term of a AP is -3 and the 10term is 15 find S10​

Answer 1

Answer:

190

Step-by-step explanation:

GIVEN THAT :

a = -3

a(10) = 15

according to the formula. {a(n) = a+(n-1)d}

a(10) = a+(10-1)d

15 = -3+(9)d

18 = 9d

d = 2

according to the formula.

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

S(10) = 10/2{2(10)+(10-1)2}

S(10) = 5{20+(9)2}

S(10) = 5(20+18)

S(10) = 5(38)

S(10) = 190

So by this solution we can

conclude that S(10) = 190

hope it's helpful