[tex]\displaystyle\bf\\1)\\\\(-3b^{5} )^{3} \cdot 2b^{3} =(-3)^{3} \cdot b^{5\cdot 3}\cdot 2b^{3}=-27\cdot 2\cdot b^{15+3} =-54b^{18}\\\\2)\\\\\frac{25^{3} \cdot 5^{2} }{5^{7} } =\frac{(5^{2} )^{3} \cdot 5^{2} }{5^{7} } =\frac{5^{6} \cdot 5^{2} }{5^{7} } =\frac{ 5^{6+2} }{5^{7} } =\frac{5^{8} }{5^{7} } =5^{8-7} =5\\\\3)\\\\(2a-b)^{2} +(a-4b)(a+4b)=\\\\=(2a)^{2} -2\cdot 2a\cdot b+b^{2} +a^{2} -(4b)^{2} =\\\\=4a^{2} -4ab+b^{2}+a^{2} -16b^{2} = 5a^{2} -4ab-15b^{2}[/tex]

1.

[tex]( - 3b {}^{5} ) {}^{3} \times 2 {b}^{3} = ( - 3) {}^{3} b {}^{5 \times 3} \times 2 {b}^{3} = - 27 {b}^{15} \times 2 {b}^{3} = \\ = - 54 {b}^{15 + 3} = - 54 {b}^{18} [/tex]

Ответ: А

2.

[tex] \frac{25 {}^{3} \times 5 {}^{2} }{ {5}^{7} } = \frac{( {5}^{2} ) {}^{3} \times {5}^{2} }{ {5}^{7} } = \frac{5 {}^{2 \times 3} \times 5 {}^{2} }{ {5}^{7} } = \frac{ {5}^{6} \times 5 {}^{2} }{ {5}^{7} } = \frac{ {5}^{6 + 2} }{ {5}^{7} } = \\= \frac{ {5}^{8} }{ {5}^{7} } = {5}^{8 - 7} = 5[/tex]

Ответ: В

3.

(2а - b)² + (a-4b)(a+4b) = 4a² - 4ab + b² + a² - 16b² = 5a² - 4ab - 15b²