Question

please answer this question

Answer 1

Hope , you understand my answer and writing .
Assuming r is positive ,
(r+1)^2 = r ^2 + 2r + 1
= >100 + ( some positive quantity)
> 100.

If r is negative , (let r = -11) ,
Here, r^2 = 121 > 100.

But, (r+1)^2 =100 which is not satisfying given inequality.

There, here we have to assume r should be positive.

Hope, it helps .