Ответ:

Объяснение:

7.

[tex]\frac{2a(a-2) + 8a}{a-2} : \frac{3(a+2)}{5(a-2)} = \frac{10}{3} a \\\frac{2a^{2} - 4a + 8a }{a-2} : \frac{3(a+2)}{5(a-2)} = \frac{10}{3}a\\ \frac{2a^{2} + 4a }{a-2} : \frac{3(a+2)}{5(a-2)} = \frac{10}{3} a \\ \frac{2a(a+2)}{a-2} * \frac{5(a-2)}{3(a+2)} = \frac{10}{3} a \\ \frac{2a * 5}{3} = \frac{10}{3} a\\\frac{10}{3} a = \frac{10}{3} a[/tex]

[tex]8.\\(\frac{5a}{2bc}) ^{3} : (\frac{45ac^{3} }{16b^{5} }) ^{2} * (\frac{3c^{2} }{2b} )^{5} \\= \frac{125a^{3} }{8b^{3} c^{3} } : \frac{2025a^{2} c^{6} }{256b^{10} } * \frac{243c^{10} }{32b^{5} } \\= \frac{125a^{3} }{8b^{3} c^{3} } * \frac{256b^{10} }{2025a^{2} c^{6} } * \frac{243c^{10} }{32b^{5} } \\= \frac{160ab^{7} }{81c^{9} } * \frac{243c^{10} }{32b^{5} } \\= 15ab^{2}c[/tex]

[tex]a = \frac{1}{9} ; b=\frac{1}{2}; c=\frac{4}{5}, to\\15 * \frac{1}{9} * (\frac{1}{2}) ^{2} * \frac{4}{5} \\= \frac{5}{3} * \frac{1}{4} * \frac{4}{5}\\ = \frac{1}{3}[/tex]