计算:
(1)$\frac {3a}{4b}÷(-9a^{2}b)$; (2)$\frac {a-b}{a^{2}+ab}÷\frac {ab-a^{2}}{a^{2}b^{2}-a^{4}}$;
(3)$\frac {2x-6}{4-4x+x^{2}}÷\frac {3-x}{(x-2)(x+3)}$; (4)$\frac {x^{2}-6x+9}{x}÷\frac {x^{2}-9}{x^{2}+3x}$;
(5)$\frac {x^{2}-4y^{2}}{x^{2}+2xy+y^{2}}×\frac {2x^{2}+2xy}{x+2y}$; (6)$\frac {x+1}{x}÷(x-\frac {1+x^{2}}{2x})$;
(7)$\frac {a+3}{1-a}÷\frac {a^{2}+3a}{a^{2}-2a+1}$; (8)$(a+1-\frac {3}{a-1})÷\frac {a^{2}-4a+4}{a-1}$;
(9)$\frac {3}{a^{2}+a}×(a^{2}-a)÷\frac {a-1}{a}$; (10)$(x^{2}-4y^{2})÷\frac {2y+x}{xy}×\frac {1}{x(2y-x)}$.
(1)$\frac {3a}{4b}÷(-9a^{2}b)$; (2)$\frac {a-b}{a^{2}+ab}÷\frac {ab-a^{2}}{a^{2}b^{2}-a^{4}}$;
(3)$\frac {2x-6}{4-4x+x^{2}}÷\frac {3-x}{(x-2)(x+3)}$; (4)$\frac {x^{2}-6x+9}{x}÷\frac {x^{2}-9}{x^{2}+3x}$;
(5)$\frac {x^{2}-4y^{2}}{x^{2}+2xy+y^{2}}×\frac {2x^{2}+2xy}{x+2y}$; (6)$\frac {x+1}{x}÷(x-\frac {1+x^{2}}{2x})$;
(7)$\frac {a+3}{1-a}÷\frac {a^{2}+3a}{a^{2}-2a+1}$; (8)$(a+1-\frac {3}{a-1})÷\frac {a^{2}-4a+4}{a-1}$;
(9)$\frac {3}{a^{2}+a}×(a^{2}-a)÷\frac {a-1}{a}$; (10)$(x^{2}-4y^{2})÷\frac {2y+x}{xy}×\frac {1}{x(2y-x)}$.
答案： (1)解：原式$=\frac{3a}{4b}×(-\frac{1}{9a^{2}b})=-\frac{1}{12ab^{2}}$
(2)解：原式$=\frac{a-b}{a(a+b)}÷\frac{-a(a-b)}{a^{2}(b^{2}-a^{2})}=\frac{a-b}{a(a+b)}×\frac{a^{2}(b-a)(b+a)}{-a(a-b)}=a-b$
(3)解：原式$=\frac{2(x-3)}{(x-2)^{2}}×\frac{(x-2)(x+3)}{-(x-3)}=\frac{2(x+3)}{-(x-2)}=\frac{2x+6}{2-x}$
(4)解：原式$=\frac{(x-3)^{2}}{x}×\frac{x(x+3)}{(x-3)(x+3)}=x-3$
(5)解：原式$=\frac{(x-2y)(x+2y)}{(x+y)^{2}}×\frac{2x(x+y)}{x+2y}=\frac{2x(x-2y)}{x+y}=\frac{2x^{2}-4xy}{x+y}$
(6)解：原式$=\frac{x+1}{x}÷(\frac{2x^{2}-1-x^{2}}{2x})=\frac{x+1}{x}×\frac{2x}{(x+1)(x-1)}=\frac{2}{x-1}$
(7)解：原式$=\frac{a+3}{1-a}×\frac{(a-1)^{2}}{a(a+3)}=\frac{(a+3)(1-a)^{2}}{a(a+3)(1-a)}=\frac{1-a}{a}$
(8)解：原式$=(\frac{a^{2}-1-3}{a-1})×\frac{a-1}{(a-2)^{2}}=\frac{(a+2)(a-2)}{a-1}×\frac{a-1}{(a-2)^{2}}=\frac{a+2}{a-2}$
(9)解：原式$=\frac{3}{a(a+1)}× a(a-1)×\frac{a}{a-1}=\frac{3a}{a+1}$
(10)解：原式$=(x-2y)(x+2y)×\frac{xy}{x+2y}×\frac{1}{x(2y-x)}=(x-2y)× y×\frac{1}{-(x-2y)}=-y$
(2)解：原式$=\frac{a-b}{a(a+b)}÷\frac{-a(a-b)}{a^{2}(b^{2}-a^{2})}=\frac{a-b}{a(a+b)}×\frac{a^{2}(b-a)(b+a)}{-a(a-b)}=a-b$
(3)解：原式$=\frac{2(x-3)}{(x-2)^{2}}×\frac{(x-2)(x+3)}{-(x-3)}=\frac{2(x+3)}{-(x-2)}=\frac{2x+6}{2-x}$
(4)解：原式$=\frac{(x-3)^{2}}{x}×\frac{x(x+3)}{(x-3)(x+3)}=x-3$
(5)解：原式$=\frac{(x-2y)(x+2y)}{(x+y)^{2}}×\frac{2x(x+y)}{x+2y}=\frac{2x(x-2y)}{x+y}=\frac{2x^{2}-4xy}{x+y}$
(6)解：原式$=\frac{x+1}{x}÷(\frac{2x^{2}-1-x^{2}}{2x})=\frac{x+1}{x}×\frac{2x}{(x+1)(x-1)}=\frac{2}{x-1}$
(7)解：原式$=\frac{a+3}{1-a}×\frac{(a-1)^{2}}{a(a+3)}=\frac{(a+3)(1-a)^{2}}{a(a+3)(1-a)}=\frac{1-a}{a}$
(8)解：原式$=(\frac{a^{2}-1-3}{a-1})×\frac{a-1}{(a-2)^{2}}=\frac{(a+2)(a-2)}{a-1}×\frac{a-1}{(a-2)^{2}}=\frac{a+2}{a-2}$
(9)解：原式$=\frac{3}{a(a+1)}× a(a-1)×\frac{a}{a-1}=\frac{3a}{a+1}$
(10)解：原式$=(x-2y)(x+2y)×\frac{xy}{x+2y}×\frac{1}{x(2y-x)}=(x-2y)× y×\frac{1}{-(x-2y)}=-y$
解析：