-25/4=5/-2x

-25/4=-5/2x

-25/4*(-2/5)=x

x=5/2

$${\mathtt{\,-\,}}{\frac{{\mathtt{25}}}{{\mathtt{4}}}} = \left({\frac{{\mathtt{5}}}{-{\mathtt{2}}}}\right){\mathtt{\,\times\,}}{\mathtt{x}} \Rightarrow {\mathtt{x}} = {\frac{{\mathtt{5}}}{{\mathtt{2}}}} \Rightarrow {\mathtt{x}} = {\mathtt{2.5}}$$