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�� 491 �) (ax-bx)/(cx+dx);�) (ac+bc)/(mc+nc);�) x2/(x2+xy);�) ab/(a-ab);�) m2n/(m2n-mn2);�) (ax-bx)/(xy+x2);�) (p2-p)/(ap-bp);�) (x2-xy)/(2xy+2x2)....

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491 �) (ax-bx)/(cx+dx);

�) (ac+bc)/(mc+nc);

�) x2/(x2+xy);

�) ab/(a-ab);

�) m2n/(m2n-mn2);

�) (ax-bx)/(xy+x2);

�) (p2-p)/(ap-bp);

�) (x2-xy)/(2xy+2x2).

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