Question

Find the sum of first 20 multiple of 7 ​

Answer 1

$a = 7 \\ an = 20 \times 7 = 140 \\ d = 7 \\ sn = 20 divided \: by2 \times 7 + 140 \\ \\ 1470$

1470 is The SN.......

Answer 2

Answer:

Step-by-step explanation: