7. Сократите дробь. 8. Сократите дробь.

7. Сократите дробь: а) $\frac{30a^2}{12ab} = \frac{6a \cdot 5a}{6a \cdot 2b} = \frac{5a}{2b}$ б) $\frac{12xz}{16xyz} = \frac{4xz \cdot 3}{4xz \cdot 4y} = \frac{3}{4y}$ в) $\frac{8xyz}{24yz} = \frac{8yz \cdot x}{8yz \cdot 3} = \frac{x}{3}$ г) $\frac{12cd}{15dc} = \frac{3cd \cdot 4}{3cd \cdot 5} = \frac{4}{5}$ е) $\frac{54cd^3}{18c^3d} = \frac{18cd \cdot 3d^2}{18cd \cdot c^2} = \frac{3d^2}{c^2}$ ж) $\frac{9ab^2}{36a^2bc} = \frac{9ab \cdot b}{9ab \cdot 4ac} = \frac{b}{4ac}$ з) $\frac{45ac}{54abk} = \frac{9a \cdot 5c}{9a \cdot 6bk} = \frac{5c}{6bk}$ и) $\frac{125k^3z}{350kz^3} = \frac{25kz \cdot 5k^2}{25kz \cdot 14z^2} = \frac{5k^2}{14z^2}$ к) $\frac{45a^3b^2x}{135a^2b^3x} = \frac{45a^2b^2x \cdot a}{45a^2b^2x \cdot 3b} = \frac{a}{3b}$ 8. Сократите дробь: а) $\frac{xy - xz}{yd - zd} = \frac{x(y - z)}{d(y - z)} = \frac{x}{d}$ в) $\frac{a^2 - 3a}{2a(a - 3)} = \frac{a(a - 3)}{2a(a - 3)} = \frac{1}{2}$ г) $\frac{2a - 6b}{5a - 15b} = \frac{2(a - 3b)}{5(a - 3b)} = \frac{2}{5}$ д) $\frac{5a - 5b}{10} = \frac{5(a - b)}{10} = \frac{a - b}{2}$ е) $\frac{at + ak}{bt + bk} = \frac{a(t + k)}{b(t + k)} = \frac{a}{b}$