1. 1) [tex]\frac{8x^{5}y^{6} }{12x^{4}y^{7} } =\frac{2x^{5}y^{6} }{3x^{4}y^{7} } =\frac{2xy^{6} }{3y^{7} }=\frac{2x}{3y}[/tex]

  2) [tex]\frac{(c-d)^{2} }{c^{2}-d^{2} } =\frac{(c-d)^{2} }{(c+d)(c-d)} =\frac{c-d}{c+d}[/tex]

  3) [tex]\frac{5a-15b}{a^{2}-9b^{2} } =\frac{5(a-3b)}{a^{2}-9b^{2} } =\frac{5(a-3b)}{(a+3b)(a-3b)}=\frac{5}{a+3b}[/tex]

2. 1) [tex]\frac{3y-2x}{x+y}-\frac{2y-3x}{x+y} =\frac{3y-2x-2y+3x}{x+y}=1[/tex]

   2)[tex]\frac{3a}{4b} +\frac{9a}{4b} =\frac{3a+9a}{4b} =\frac{12a}{4b}=\frac{3a}{b}[/tex]

  3) [tex]\frac{h^{2} }{h+g} -\frac{g^{2} }{h+g} =\frac{h^{2}-g^{2} }{h+g } =\frac{(h+g)(h-g)}{h+g} =h-g[/tex]

корону пожалуйста