[tex]\displaystyle\bf\\1)\\\\\frac{c+4}{c^{2} } -\frac{2}{c} =\frac{c+4-2\cdot c}{c^{2} } =\frac{c+4-2c}{c^{2} } =\frac{4-c}{c^{2} } \\\\2)\\\\\frac{5m+n}{m^{2} n}+\frac{m-5n}{mn^{2} } =\frac{(5m+n)\cdot n+(m-5n)\cdot m}{m^{2} n^{2} } =\\\\\\=\frac{5mn+n^{2} +m^{2} -5mn}{m^{2} n^{2} } =\frac{m^{2}+n^{2} }{m^{2} n^{2} }[/tex]