V.- División de fracciones

617.

$\frac{x^{3}-x}{3x-6}:\frac{5x-5}{2x-4}$

618.

$\frac{5m^{2}c^{2}-20n^{2}d^{2}}{mc+2nd}:\frac{x^{2}-y^{2}}{x-y}$

619.

$\frac{12a^{2}x^{2}-3b^{2}y^{2}}{8ax+4by}:\frac{x^{2}-y^{2}}{x+y}$

620.

$\frac{x^{2}y^{2}-xyz+z^{2}}{xy-z}:\frac{x^{2}y^{2}-z^{2}}{xy+z}$

621.

$(x^{2}-y^{2}):(\frac{1}{x}+\frac{1}{y})$

622.

$(a+\frac{c}{d}):(b+\frac{m}{n})$

623.

$(a-\frac{a^{2}}{a-b}):(b-\frac{b^{2}}{a+b})$

624.

$(x-\frac{x-y}{1+xy}):(1+\frac{x(x-y)}{1+xy})$

625.

$\frac{x^{4}-y^{4}}{x^{3}-y^{3}}:\frac{x^{2}+y^{2}}{x^{2}+xy+y^{2}}$

626.

$(1+\frac{x-a}{x+a}):(\frac{x+a}{x-a}+1)$

626.

$\large \frac{\frac{a}{b}-\frac{b}{a}}{\frac{a}{b^{2}}-\frac{b}{a^{2}}}:\frac{\frac{1}{a}+\frac{1}{2}}{\frac{a+b}{2a}+\frac{a-b}{2b}}$