Respuesta :

mjankiewicz
a ≥ 0

[tex]-\not9^3\sqrt{28a^2}*\frac{1}{\not3^1}\sqrt{63a}=\\\\ =-3a\sqrt{4*7}*\sqrt{9*7a}=\\\\=-3a*2\sqrt{7}*3\sqrt{7a}\\\\ =-18a\sqrt7*\sqrt 7*\sqrt a=\\\\=-18a*(\sqrt7)^2*\sqrt a =\\\\ =-18a*7*\sqrt a=\\\\ =-126a\sqrt a[/tex]