Respuesta :

Answer:

-7x⁹

Step-by-step explanation:

[tex]\sqrt{49x^{18}} = \sqrt{(7^2)(x^9)^2} =\sqrt{(7x^{9})^2} = |7x^9|[/tex]

Since  x < 0 ,then |7x⁹| = -7x⁹