$\begin{array}{l} a_1 )\,\, \dfrac{-32}4<x<\dfrac{-28}{7} \\\to-8<x<-4 \\\to x \in \{-7;-6;-5\} \\\to A=\{-7;-6;-5\} \\\,\\ a_2)\,\,\dfrac{-28}4<x<\dfrac{-21}7 \\\to -7<x<-3\\\to x\in\{-6;-5;-4\}\\\to A=\{-6;-5;-4\} \\\,\\a_3)\,\,\dfrac{-27}3<x<\dfrac{12}4 \\\to -9<x<3 \\\to x \in \{-8;-7;-6;-5;...;1;2\} \\\to A=\{-8;-7;-6;-5;...;1;2\} \\\,\\b_1)\,\,\dfrac{-35}7<x<-1 \\\to -5<x<-1 \\\to x \in \{-4;-3;-2\} \\\to A=\{-4;-3;-2\} \\\,\\ b_2)\,\,\dfrac{-30}6<x<\dfrac{-12}6 \\\to -5<x<-2 \\\to x \in \{-4;-3\} \\\to A = \{-4;-3\} \\\,\\ c_1)\,\,\dfrac{-18}6<x<\dfrac{144}{72} \\\to -3<x<2 \\\to x \in \{-2;-1;0;1\} \\\to A=\{-2;-1;0;1\} \\\,\\ c_2)\,\,\dfrac{-21}7<x<\dfrac{-12}6 \\\to -3<x<-2 \\\to x \in \varnothing \\\to A = \varnothing \\\,\\ d_1)\,\,\dfrac{-30}5<x<\dfrac{-45}9 \\\to -6<x<-5 \\\to x \in \varnothing \\\to A=\varnothing \\\,\\d_2)\,\,\dfrac{-36}9 <x<\dfrac{-15}5 \\\to -4<x<-3 \\\to x \in \varnothing \\\to A = \varnothing \end{array}$
Câu `b_1` và `d_2` mình sửa đề nhé, nếu đề bạn viết đúng thì bình luận để mình sửa!
