Question

The sum of first 63terms of the Ap -19,-13,​

Answer 1

Answer:

a=-19

d=-13-(-19)

d=-13+19

d=6

$sum = \frac{63}{2} (2 \times - 19 + (63 - 1)6 \\ \frac{63}{2} ( - 38 + (62)6) \\ \frac{63}{2} ( - 38 + 372) \\ \frac{63}{2} (334) \\ 63 \times 167 \\ 10521is \: the \: answer$

Answer 2

Answer:

a1=-19

a2=-13

d=a2-a1=-13-(-19)

  =-13+19=6

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

S63 =63/2[2*-19+(63-1)6]

       =31.5*[-38+372]

        =31.5*334

        =10521

Step-by-step explanation: