Question

find the sum of the first 51 terms of A.P., which second and third terms are 14 and 18brespectively​

Answer 1

Answer:

answer is 5610

Step-by-step explanation:

Here, second term = a2 = 14

Third term = a3 = 18

∴ Common difference = a3 - a2 = 18 - 14 = 4

Thus first term = a = a2 - d = 14 - 4 = 10

Now, Sum of first n terms of an AP is given by

Sn =

[2a + (n - 1)d]

∴ Sum of first 51 terms is given by:

S51 =

[2(10) + (51 - 1)(4)]

= (51/2) × [20 + 200]

= (51/2) × 220

= (51) × 110

= 5610

∴ S51 = 5610

Answer 2

hope it will help you....

please mark me brainliest!!!!!