Question

помогите с пределами, умоляю (((

Answer 1

$lim_{xto 3}frac{sqrt{x+6}-sqrt{10x-21}}{5x-15}=lim_{xto 3}, frac{(x+6)-(10x-21)}{5(x-3)(sqrt{x+6}+sqrt{10x-21})}=\\=lim_{xto 3}, frac{-9(x-3)}{5(x-3)(sqrt{x+6}+sqrt{10x-21})}=frac{-9}{5(sqrt9+sqrt9)}=frac{-9}{5(3+3)}=-frac{3}{10}$