Привет! Давай разберем второй вариант.
\[ x^{12} \cdot x^3 = x^{12+3} = x^{15} \]
\[ a^{-3} \cdot a^8 = a^{-3+8} = a^5 \]
\[ t^{-5} \cdot t = t^{-5+1} = t^{-4} \]
\[ y^4 \cdot y^{-4} = y^{4+(-4)} = y^0 = 1 \]
\[ m^9 : m^5 = m^{9-5} = m^4 \]
\[ n^{-12} : n^{-8} = n^{-12 - (-8)} = n^{-12+8} = n^{-4} \]
\[ (s^3)^7 = s^{3 \times 7} = s^{21} \]
\[ (x^{-4})^5 = x^{-4 \times 5} = x^{-20} \]
\[ (k^{-7})^{-2} = k^{-7 \times (-2)} = k^{14} \]
\[ (x^6 y)^{-4} = (x^6)^{-4} y^{-4} = x^{-24} y^{-4} \]
\[ \left( \frac{a^{-4}}{b} \right)^{-3} = \frac{(a^{-4})^{-3}}{b^{-3}} = \frac{a^{12}}{b^{-3}} = a^{12} b^3 \]
\[ 2^4 : 2^8 = 2^{4-8} = 2^{-4} = \frac{1}{2^4} = \frac{1}{16} \]
\[ (4^{-1})^{-2} = 4^{(-1) \times (-2)} = 4^2 = 16 \]
\[ 14^{-7} : 14^{-8} = 14^{-7 - (-8)} = 14^{-7+8} = 14^1 = 14 \]
\[ \frac{14a}{b^{-3}} \cdot \frac{b^{-2}}{56a^4} = \frac{14a \cdot b^{-2}}{b^{-3} \cdot 56a^4} = \frac{14}{56} \cdot \frac{a}{a^4} \cdot \frac{b^{-2}}{b^{-3}} = \frac{1}{4} \cdot a^{1-4} \cdot b^{-2 - (-3)} = \frac{1}{4} a^{-3} b^1 = \frac{b}{4a^3} \]
\[ \frac{18x^{-6}}{y^5} \cdot \frac{7y^{-5}}{6x^{-12}} = \frac{18 \cdot 7}{6} \cdot \frac{x^{-6}}{x^{-12}} \cdot \frac{y^{-5}}{y^5} = 3 \cdot 7 \cdot x^{-6 - (-12)} \cdot y^{-5-5} = 21 \cdot x^6 \cdot y^{-10} = \frac{21x^6}{y^{10}} \]