Page:The Algebra of Mohammed Ben Musa (1831).djvu/207

 وكذلك فافعل] The same structure occurs page 21, line 15.

فهذه الستة الضروب], in his article on Algebra, quotes the following observation from Ibn Khaldun قال ابن خلدون وقد بلغنا أن بعض ائمة التعاليم من اهل المشرق انتهي المعادلات الي اكثر من هذه الستة وبلغها الي فوق العشرين واستخرج لها كلها اعمالا وثيقة ببراهين هندسية “ remarks: A report has reached us, that some great scholars of the east have increased the number of cases beyond six, and have brought them to upwards of twenty, producing their accurate solutions together with geometrical demonstrations.”

See geometrical illustration of the three cases involving an affected square, as reported by  (I. p. 2.), and hence by  (Tracts, &c., II. p. 198.), in the introduction of his Ars magna, distinctly refers to the demonstrations of the three cases given by our author, and distinguishes them from others which are his own. At etiam demonstrationes, præter tres et duas  (,  pupil), omnes nostræ sunt.—In another passage (page 20) he blames our author for having given the demonstration of only one solution of the case $$cx^2+a=bx$$. Nec admireris,