Алгебра 8 класс учебник Макарычев, Миндюк ответы – номер 987

а) $$ \left\{\begin{array} { l } { y \geq 0 } \\ { 7 , 2 - y \geq 4 } \end{array} \left\{\begin{array}{l} y \geq 0 \\ -y \geq 4-7,2 \end{array}\right.\right. $$ $$ \left\{\begin{array}{l} y \geq 0 \\ y \leq-3,2 \end{array}:(-1)\left\{\begin{array}{l} y \geq 0 \\ y \leq 3,2 \end{array}\right.\right. $$

    [0; 3,2]
б) $$ \left\{\begin{array} { l } { 1 2 a - 3 7 > 0 } \\ { 6 a \leq 4 2 } \end{array} \left\{\begin{array}{l} 12 a>37 \\ 6 a \leq 42 \end{array}\right.\right. $$ $$ \left\{\begin{array} { l } { a > 3 7 : 1 2 } \\ { a \leq 4 2 : 6 } \end{array} \left\{\begin{array}{l} a>3 \frac{1}{12} \\ a \leq 7 \end{array}\right.\right. $$

    (31/12; 7]
в) $$ \left\{\begin{array} { l } { 6 - 4 b > 0 } \\ { 3 b - 1 > 0 } \end{array} \left\{\begin{array}{l} -4 b>-6 \\ 3 b>1 \end{array}\right.\right. $$ $$ \left\{\begin{array} { l } { b < - 6 : ( - 4 ) } \\ { b > 1 : 3 } \end{array} \left\{\begin{array}{l} b<\frac{3}{2} \\ b>\frac{1}{3} \end{array}\right.\right. $$

    (1/3; 3/2)
г) $$ \left\{\begin{array} { l } { 3 - 1 , 8 x < 0 } \\ { 0 , 2 - 0 , 1 x > 0 } \end{array} \left\{\begin{array}{l} -1,8 x<-3 \\ -0,1 x>-0,2 \end{array}\right.\right. $$ $$ \left\{\begin{array} { l } { x > - 3 : ( - 1 , 8 ) } \\ { x < - 0 , 2 : ( - 0 , 1 ) } \end{array} \left\{\begin{array}{l} x>\frac{5}{3} \\ x<2 \end{array}\right.\right. $$

    (5/3; 2)