Find the sum of sequence, 7, 77, 777, 7777..... to n terms ???

plz ans fast....

its very urgent

70/81(10

^{n}-1) - 7n/9

**ANSWER**

Keep posting !!

Keep posting !!

**
**

Find the sum of sequence, 7, 77, 777, 7777..... to n terms ???

plz ans fast....

its very urgent

70/81(10

Keep posting !!

**
**

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