Алгебра 8 класс учебник Макарычев, Миндюк ответы – номер 981

а) $$ \left\{\begin{array} { l } { 5 7 - 7 x > 3 x - 2 } \\ { 2 2 x - 1 < 2 x + 4 7 } \end{array} \left\{\begin{array}{l} -7 x-3 x>-2-57 \\ 22 x-2 x<47+1 \end{array}\right.\right. $$ $$ \left\{\begin{array} { l } { - 1 0 x > - 5 9 } \\ { 2 0 x < 4 8 } \end{array} \left\{\begin{array} { l } { x < - 5 9 : ( - 1 0 ) } \\ { x < 4 8 : 2 0 } \end{array} \left\{\begin{array}{l} x<5,9 \\ x<2,4 \end{array}\right.\right.\right. $$

     (−∞; 2,4)
б) $$ \left\{\begin{array} { l } { 1 - 1 2 y < 3 y + 1 } \\ { 2 - 6 y > 4 + 4 y } \end{array} \left\{\begin{array}{l} -12 y-3 y<1-1 \\ -6 y-4 y>4-2 \end{array}\right.\right. $$ $$ \left\{\begin{array} { l } { - 1 5 y < 0 } \\ { - 1 0 y > 2 } \end{array} \left\{\begin{array} { l } { y > 0 : ( - 1 5 ) } \\ { y < 2 : ( - 1 0 ) } \end{array} \left\{\begin{array}{l} y>0 \\ y<-0,2 \end{array}\right.\right.\right. $$

     Нет решения
в) $$ \left\{\begin{array} { l } { 1 0 2 - 7 3 z > 2 z + 2 } \\ { 8 1 + 1 1 z \geq 1 + z } \end{array} \left\{\begin{array}{l} -73 z-2 z>2-102 \\ 11 z-z \geq 1-81 \end{array}\right.\right. $$ $$ \left\{\begin{array} { l } { - 7 5 z > - 1 0 0 } \\ { 1 0 z \geq - 8 0 } \end{array} \left\{\begin{array} { l } { z < - 1 0 0 : ( - 7 5 ) } \\ { z \geq - 8 0 : 1 0 } \end{array} \left\{\begin{array}{l} z<1 \frac{1}{3} \\ z \geq-8 \end{array}\right.\right.\right. $$

     [−8; 11/3)
г) $$ \left\{\begin{array} { l } { 6 + 6 , 2 x \geq 1 2 - 1 , 8 x } \\ { 2 - x \geq 3 , 5 - 2 x } \end{array} \left\{\begin{array}{l} 6,2 x+1,8 x \geq 12-6 \\ -x+2 x \geq 3,5-2 \end{array}\right.\right. $$ $$ \left\{\begin{array} { l } { 8 x \geq 6 } \\ { x \geq 1 , 5 } \end{array} \left\{\begin{array} { l } { x \geq 6 : 8 } \\ { x \geq 1 , 5 } \end{array} \left\{\begin{array}{l} x \geq 0,75 \\ x \geq 1,5 \end{array}\right.\right.\right. $$

     [1,5; +∞)