Алгебра 8 класс учебник Макарычев, Миндюк ответы – номер 980

а) $$ \left\{\begin{array} { l } { 2 x - 1 < 1 , 4 - x } \\ { 3 x - 2 > x - 4 } \end{array} \left\{\begin{array}{l} 2 x+x<1,4+1 \\ 3 x-x>-4+2 \end{array}\right.\right. $$ $$ \left\{\begin{array} { l } { 3 x < 2 , 4 } \\ { 2 x > - 2 } \end{array} \left\{\begin{array} { l } { x < 2 , 4 : 3 } \\ { x > - 2 : 2 } \end{array} \left\{\begin{array}{l} x<0,8 \\ x>-1 \end{array}\right.\right.\right. $$

     (−1; 0,8)
б) $$ \left\{\begin{array} { l } { 5 x + 6 \leq x } \\ { 3 x + 1 2 \leq x + 1 7 } \end{array} \left\{\begin{array}{l} 5 x-x \leq-6 \\ 3 x-x \leq 17-12 \end{array}\right.\right. $$ $$ \left\{\begin{array} { l } { 4 x \leq - 6 } \\ { 2 x \leq 5 } \end{array} \left\{\begin{array} { l } { x \leq - 6 : 4 } \\ { x \leq 5 : 2 } \end{array} \left\{\begin{array}{l} x \leq-1,5 \\ x \leq 2,5 \end{array}\right.\right.\right. $$

     (−∞; 2,5]
в) $$ \left\{\begin{array} { l } { 1 7 x - 2 > 1 2 x - 1 } \\ { 3 - 9 x < 1 - x } \end{array} \left\{\begin{array}{l} 17 x-12 x>-1+2 \\ -9 x+x<1-3 \end{array}\right.\right. $$ $$ \left\{\begin{array} { l } { 5 x > 1 } \\ { - 8 x < - 2 } \end{array} \left\{\begin{array} { l } { x > 1 : 5 } \\ { x > - 2 : ( - 8 ) } \end{array} \left\{\begin{array}{l} x>0,2 \\ x>0,25 \end{array}\right.\right.\right. $$

     (0,25; +∞)
г) $$ \left\{\begin{array} { l } { 2 5 - 6 x \leq 4 + x } \\ { 3 x + 7 , 7 > 1 + 4 x } \end{array} \left\{\begin{array}{l} -6 x-x \leq 4-25 \\ 3 x-4 x>1-7,7 \end{array}\right.\right. $$ $$ \left\{\begin{array} { l } { - 7 x \leq - 2 1 } \\ { - x > - 6 , 7 } \end{array} \left\{\begin{array} { l } { x \geq - 2 1 : ( - 7 ) } \\ { x < - 6 , 7 : ( - 1 ) } \end{array} \left\{\begin{array}{l} x \geq 3 \\ x<6,7 \end{array}\right.\right.\right. $$

     [3; 6,7)