Find the sum of the first 17 term of an AP whose 4th term = -15 and 9th term = -30.

### Asked by arindeep.singh | 26th Jun, 2020, 03:34: PM

Expert Answer:

### 4th term = -15 and 9th term = -90
a + 3d = -15 ... (i) and
a + 8d = -30 ... (ii)
Subtracting (ii) from (ii), we get
5d = -15
d = -3
Substituting the value of d in (i), we get
a + 3(-3) = -15
a - 9 = -15
a = -6
Sum of n terms if given by

### Answered by Renu Varma | 28th Jun, 2020, 05:14: PM

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