Question

how it came . Explain
HOPEyou guys will help me

​

Answer 1

Answer:

Let radius be r

$\pi {r}^{2} = \pi {x}^{2} + 6\pi \: x + 9\pi \\ {r}^{2} = {x}^{2} + 6x + 9 \\ {r}^{2} = {x}^{2} + 2(3)x + {3}^{2} \\ {r}^{2} = (x + 3)^2 \\ r = \pm(x + 3)$