Question

the first term of an A. P is -3 and the 10th term is 15 find S10


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Answer 1

Answer:

Step-by-step explanation=

Answer 2

Answer:

165

Step-by-step explanation:

a= -3

a10=15

a+ 9d=15

-3+9d=15

9d=15+3

9d=18

d=18/9

d=2

S15=15/2(2×-3+14×2)

S15=15/2(-6+28)

S15=15/2 ×22

S15=15 ×11

S15=165