Atrisiniet =sqrt{x^2+6x+9}=m^2+2m

$$= \sqrt { x ^ { 2 } + 6 x + 9 } = m ^ { 2 } + 2 m$$

Atrast m (complex solution)

$$m=-\sqrt{\sqrt{\left(x+3\right)^{2}}+1}-1$$

$$m=\sqrt{\sqrt{\left(x+3\right)^{2}}+1}-1$$

Atrast x (complex solution)

$$x=-\left(m^{2}+2m+3\right)$$

$$x=\left(m-1\right)\left(m+3\right)\text{, }arg(m\left(m+2\right))<\pi \text{ or }m=-2\text{ or }m=0$$

Atrast m

$$m=-\sqrt{|x+3|+1}-1$$

$$m=\sqrt{|x+3|+1}-1$$

Atrast x

$$x=\left(m-1\right)\left(m+3\right)$$

$$x=-m\left(m+2\right)-3\text{, }m\leq -2\text{ or }m\geq 0$$