Verified answer

Ответ:

Применяем свойства неравенств .

  [tex]3 < x < 4\ \ ,\ \ 1 < y < 4\\\\a)\ \ -4 < -y < -1\ \ \to \ \ \ 3-4 < x-y < 4-1\ \ ,\ \ \boldsymbol{-1 < x-y < 3}\\\\b)\ \ 2 < 2y < 8\ \ ,\ \ -4 < -x < -3\ \ \to \ \ \ 2-4 < 2y-x < 8-3\ \ ,\\\\\boldsymbol{-2 < 2y-x < 5}\\\\c)\ \ 6 < 2x < 8\ \ ,\ \ -12 < -3y < -3\ \ \ \to \ \ \ 6-12 < 2x-3y < 8-3\ \ ,\\\\\boldsymbol{-6 < 2x-3y < 5}\\\\d)\ \ 9 < 3x < 12\ \ ,\ \ 2 < 2y < 8\ \ ,\ \ \dfrac{1}{8} < \dfrac{1}{2y} < \dfrac{1}{2}\ \ \ \to \\\\\dfrac{9}{8} < \dfrac{3x}{2y} < \dfrac{12}{2}\ \ ,\ \ \ \boldsymbol{1\dfrac{1}{8} < \dfrac{3x}{2y} < 6}[/tex]