Answer:
[tex]xy^4[/tex]
Step-by-step explanation:
So, we're going to name this unknown number, z. Our new objective is to solve for z.
[tex]x\ne \:0\\=\frac{x^{11}y^9z}{x^{11}y^9}=\frac{x^{12}y^{13}}{x^{11}y^9}\\=\frac{zy^9}{y^9} = z\\\frac{x^{12}y^{13}}{x^{11}y^9}\\\frac{x^{12}}{x^{11}}=x^{12-11}\\\frac{y^{13}x^{12-11}}{y^9}\\\frac{xy^{13}}{y^9}\\\frac{y^{13}}{y^9}=y^{13-9}\\xy^{13-9}\\z =xy^4[/tex]
