1) [tex]A=(x+3)(y+1)\\A=xy+x+3y+3\\\\B=(2x+5)(3x+2)\\B=6x^{2} +4x+15x+10\\B=6x^{2} +19x+10\\\\C=(x-2)(6x+7)\\C=6x^{2} +7x-12x-14=6x^{2} -5x-14\\\\D=(3a-2)(a-3)=3a^{2}-9a-2a+6=3a^{2}-11a+6\\\\E=(3-y)(y-6)=3y-18-y^{2} +6y=-y^{2}+9y-18\\\\F=(-5x-1)(2x-3)=-10x^{2}+15x-2x+3=-10x^{2}+13x+3\\\\Dans chaque cas il faut appliquer la double distributivité et additionner les termes de meme nature.[/tex]
2)
[tex]A= \frac{\frac{1}{3} +\frac{3}{4} }{\frac{5}{4} -\frac{7}{3}} \\\\A= \frac{\frac{4}{12} +\frac{9}{12} }{\frac{15}{12} -\frac{28}{12}} \\\\A=\frac{\frac{13}{12} }{\frac{-13}{12} } = -1[/tex]
