Question

Допооооможіть!!!!!!! даю 100 балов

Answer 1

$displaystylettboxed{1}\\ frac{63x^2y^2}{42x^6y^5}= frac{3}{2x^4y^3}\\\ frac{49-a^2}{3a^2-21a}=frac{(7-a)(7+a)}{-3a(7-a)}=-frac{7+a}{3a}\\\ frac{(5-x)^2}{3x^2-30x+75}=frac{(5-x)^2}{3(25-10x+x^2)}=frac{(5-x)^2}{3(5-x)^2}=frac{1}{3}$

$displaystylettboxed{2}\\ frac{d}{c-d}=frac{d(c+d)}{(c-d)(c+d)}= frac{cd+d^2}{c^2-d^2}$

$displaystylettboxed{3}\\ frac{m^2+6m+9}{9-m^2}= frac{(m+3)^2}{(3-m)(3+m)}=frac{m+3}{3-m}=frac{7+3}{3-7}=frac{10}{-4}=-2.5$