Question

The first term of an A.P.is - 5 and the 6th term is 45. Find S6​

Answer 1

Answer : 120 ✔

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Solution :

Given that :

a = -5, T6 = 45

As we know that :

Tn = a + (n - 1)d

=> T6 = -5 + (6 - 1)d

=> 45 = -5 + 5d

=> 5d = 45 + 5

=> 5d = 50

=> d = 10

Also we know that :

Sn = n/2[ 2a + (n - 1)d ]

=> S6 = 6/2[ 2×(-5) + (6-1)10 ]

=> S6 = 3[ -10 + 50 ]

=> S6 = 3 × 40 = 120

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Hope it helps you ☺☺

Fóllòw Më ❤

Answer 2

Answer:

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