Объяснение:
\frac{x^{2} -y^{2} }{5x^{2} } :\frac{x^{2}-2xy+y^{2} }{25x}=\frac{x^{2} -y^{2} }{5x^{2} }*\frac{25x}{(x-y)^{2} } =\frac{(x+y)*(x-y)*25x}{5x^{2}*(x-y)^{2} } =\frac{5*(x+y)}{x*(x-y)} =\frac{5*(2+1)}{2*(2-1)}=\\=\frac{5*3}{2*1}=\frac{15}{2}=7,5.
