2) а) $$rac{5a^2}{6a}$$ б) $$rac{9b^4}{10b^3}$$ в) $$rac{-5c^4}{10c^5}$$ г) $$rac{3x^4}{21z^8}$$ д) $$rac{x^3}{39z}$$ e) $$rac{-42y^5}{12y^3}$$

2) а) $$rac{5a^2}{6a} = \frac{5a}{6}$$ б) $$rac{9b^4}{10b^3} = \frac{9b}{10}$$ в) $$rac{-5c^4}{10c^5} = -\frac{1}{2c}$$ г) $$rac{3x^4}{21z^8} = \frac{x^4}{7z^8}$$ д) $$rac{x^3}{39z}$$ - не сокращается e) $$rac{-42y^5}{12y^3} = -\frac{7y^2}{2}$$