Выполни деление выражений: a) m²-3m/8x² : 3m/8x

a) $\frac{m^2-3m}{8x^2} : \frac{3m}{8x} = \frac{m(m-3)}{8x^2} \cdot \frac{8x}{3m} = \frac{m-3}{3x}$ б) $\frac{5a^2}{6b^3} : \frac{a^3}{ab-b^2} = \frac{5a^2}{6b^3} : \frac{a^3}{b(a-b)} = \frac{5a^2}{6b^3} \cdot \frac{b(a-b)}{a^3} = \frac{5(a-b)}{6ba}$ в) $\frac{x^2 + x^3}{11a^2} : \frac{4+4x}{a^3} = \frac{x^2(1+x)}{11a^2} : \frac{4(1+x)}{a^3} = \frac{x^2(1+x)}{11a^2} \cdot \frac{a^3}{4(1+x)} = \frac{x^2a}{44}$ г) $\frac{6ax}{m^2-2m} : \frac{8ax}{3m-6} = \frac{6ax}{m(m-2)} : \frac{8ax}{3(m-2)} = \frac{6ax}{m(m-2)} \cdot \frac{3(m-2)}{8ax} = \frac{9}{4m}$ д) $\frac{a^2-3ab}{3b} : (7a-21b) = \frac{a(a-3b)}{3b} : (7(a-3b)) = \frac{a(a-3b)}{3b} \cdot \frac{1}{7(a-3b)} = \frac{a}{21b}$ е) $(x^2 - 4y^2) : \frac{5x-10y}{x} = ((x-2y)(x+2y)) : \frac{5(x-2y)}{x} = (x-2y)(x+2y) \cdot \frac{x}{5(x-2y)} = \frac{x(x+2y)}{5}$ ж) $\frac{(2a-b)^2}{3} : \frac{4a^3 - ab^2}{3} = \frac{(2a-b)^2}{3} : \frac{a(4a^2 - b^2)}{3} = \frac{(2a-b)^2}{3} : \frac{a(2a-b)(2a+b)}{3} = \frac{(2a-b)^2}{3} \cdot \frac{3}{a(2a-b)(2a+b)} = \frac{2a-b}{a(2a+b)}$ з) $\frac{10m-15n}{2m} : (2m-3n)^2 = \frac{5(2m-3n)}{2m} : (2m-3n)^2 = \frac{5(2m-3n)}{2m} \cdot \frac{1}{(2m-3n)^2} = \frac{5}{2m(2m-3n)}$