[tex]\displaystyle\bf\\1)\\\\\frac{18z+1}{z-3} +\frac{18z-1}{z+3} =\frac{(18z+1)\cdot(z+3)+(18z-1)\cdot(z-3)}{(z-3)\cdot(z+3)} =\\\\\\=\frac{18z^{2} +54z+z+3+18z^{2}-54z-z+3 }{z^{2} -9} =\frac{36z^{2} +6}{z^{2}-9 } \\\\\\2)\\\\\frac{z^{2}-9 }{6z^{2} +1} \cdot\frac{36z^{2}+6 }{z^{2} -9} =\frac{z^{2}-9 }{6z^{2} +1} \cdot\frac{6\cdot(6z^{2}+1) }{z^{2} -9} =6\\\\\\Otvet \ : \ 6[/tex]