I.- Simplificar fracciones


500.		501.

$\frac{12a^{4}b^{2}c}{3a^{3}bc}$		$\frac{10a^{2}bc}{-5ab}$


502.		503.

$\frac{-15a^{2}bc^{2}d^{3}}{5abc^{2}d}$		$\frac{-12a^{2}x}{-28ax^{2}}$


504.		505.

$\frac{10ab^{2}x^{4}y}{15b^{3}x^{2}y^{3}z}$		$\frac{-20abc^{3}}{2ab^{2}}$


506.		507.

$\frac{-18a^{3}bc^{2}x}{-36a^{4}b^{2}x}$		$\frac{3a^{2}b}{18a^{3}b^{2}}$


508.		509.

$\frac{-12acx^{2}}{26a^{2}c^{2}x}$		$\frac{38m^{3}n^{4}r^{2}}{57m^{4}n^{4}r}$


510.		511.

$\frac{b+b^{2}}{a+ab}$		$\frac{a^{2}-b^{2}}{a^{2}-2ab+b^{2}}$


512.		513.

$\frac{x^{2}-x}{xy-x}$		$\frac{x^{3}-1}{x-1}$


514.		515.

$\frac{x^{2}-y}{x^{2}-1}$		$\frac{4a^{2}b^{3}-8a^{3}b^{3}}{12a^{2}b^{4}+4a^{4}b^{4}}$


516.		517.

$\frac{x^{2}-9y^{2}}{ax-3ay}$		$\frac{x^{3}-x}{(x-1)(x+1)^{2}}$


518.		519.

$\frac{12x^{2}y-18xy^{2}}{10ax^{3}y^{2}-15ax^{2}y^{3}}$		$\frac{5x^{3}y^{4}-10x^{2}y^{3}}{7x^{4}y^{2}-14x^{3}y}$


520.		521.

$\frac{ax^{2}-a^{3}}{bx^{2}-a^{2}b}$		$\frac{35xz-45yz}{7x-9y}$


522.		523.

$\frac{ax+by}{ax^{2}-bxy}$		$\frac{2a^{2}+4ab}{3ab+6b^{2}}$


524.		525.

$\frac{16x^{3}y-20x^{2}z}{28x^{2}y^{3}z^{3}-35xy^{2}z^{3}}$		$\frac{(a-b)^{2}}{a^{2}-b^{4}}$


526.		527.

$\frac{a^{3}+b^{3}}{a^{2}-b^{2}}$		$\frac{x^{2}+4x+4}{x^{2}-4}$


528.		529.

$\frac{6a^{3}-21a^{2}+15a}{2a^{2}+7a+5}$		$\frac{3a^{2}-6a+3}{6ax-6x}$

530.

$\bg_black \frac{a^{2}x-2ax+x}{2a^{3}-6a^{2}+6a+2}$

531.

$\frac{5a^{3}-10a^{2}b+5ab^{2}}{8a^{3}-8a^{2}b}$


532.		533.

$\frac{7a-7b-7c}{21a-21b-21c}$		$\frac{9a^{5}-4a}{6a^{2}b^{2}-4b^{2}}$


534.		535.

$\frac{x^{2}+4x+4}{x^{2}-4}$		$\frac{a^{4}-x^{4}}{a^{3}x-ax^{3}}$

536.

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

537.

$\frac{xy-3x-5y+15}{xy-3x}$

538.

$\frac{xy-2y+x-2}{xy+x-5y-5}$

539.

$\frac{a^{2}-2ab+b^{2}}{a^{2}-a(b+c)+bc}$

540

$\frac{a^{2}+b^{2}+c^{2}+2ab}{a^{2}+c^{2}-b^{2}+2ac}$

541.

$\frac{a^{2}-b^{2}-ac-bc}{a^{2}-b^{2}}$

542.

$\frac{(a+b)^{2}-(a-b)^{2}}{8abx}$

543.

$\frac{(x^{2}-4)(x^{2}-2x+1)}{x(x^{2}-1)-2(x^{2}-1)}$

544.

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

545.

$\frac{(a-1)(a+1)^{2}}{a^{3}-a}$

546.

$\frac{(a+b)^{2}-4ab}{2a-2b}$