$=\frac{54x^{6}y^{9}}{9x^{2}y^{4}}$
Factor the number: $ 54=9\cdot 6$$=\frac{9\cdot 6x^{6}y^{9}}{9x^{2}y^{4}}$
Cancel the common factor: $ 9$$=\frac{6x^{6}y^{9}}{x^{2}y^{4}}$
Simplify $\frac{x^{6}}{x^{2}}:{\quad}x^{4}$$=\frac{6x^{4}y^{9}}{y^{4}}$
Simplify $\frac{y^{9}}{y^{4}}:{\quad}y^{5}$$=6x^{4}y^{5}$