0\\\\5x^3y\sqrt3=-\sqrt{5^2\cdot (x^3)^2\cdot y^2\cdot 3}=-\sqrt{75x^6y^2}\\\\\\P.S.\; \; \; \; A\sqrt{B}=\left \{ {{\sqrt{A^2\cdot B}\; ,\; esli\; A>0} \atop {-\sqrt{A^2\cdot B}}\; ,\; esli\; A<0} \right." alt="x<0\; ,\; \; y>0\\\\5x^3y\sqrt3=-\sqrt{5^2\cdot (x^3)^2\cdot y^2\cdot 3}=-\sqrt{75x^6y^2}\\\\\\P.S.\; \; \; \; A\sqrt{B}=\left \{ {{\sqrt{A^2\cdot B}\; ,\; esli\; A>0} \atop {-\sqrt{A^2\cdot B}}\; ,\; esli\; A<0} \right." align="absmiddle" class="latex-formula">