$${\frac{{\mathtt{9}}}{{\mathtt{4}}}}{\mathtt{\,\times\,}}{\mathtt{x}} = {\mathtt{18}}$$ => $${\mathtt{x}} = {\frac{{\mathtt{4}}{\mathtt{\,\times\,}}{\mathtt{18}}}{{\mathtt{9}}}} = {\mathtt{8}}$$
$${\frac{{\mathtt{9}}}{{\mathtt{4}}}}{\mathtt{\,\times\,}}{\mathtt{x}} = {\mathtt{18}}$$ => $${\mathtt{x}} = {\frac{{\mathtt{4}}{\mathtt{\,\times\,}}{\mathtt{18}}}{{\mathtt{9}}}} = {\mathtt{8}}$$