Giúp mik làm câu này với

Đáp án+Giải thích các bước giải:

$9)\\ C=\dfrac{x+2}{x+3} -\dfrac{5}{x^2+x-6}+\dfrac{1}{2-x} (x\ne 2; x \ne -3)\\  a) C=\dfrac{x+2}{x+3} -\dfrac{5}{x^2+x-6}+\dfrac{1}{2-x} \\ =\dfrac{x+2}{x+3} -\dfrac{5}{(x^2-2x)+(3x-6)}-\dfrac{1}{x-2} \\ =\dfrac{x+2}{x+3} -\dfrac{5}{x(x-2)+3(x-2)}-\dfrac{1}{x-2} \\ =\dfrac{x+2}{x+3} -\dfrac{5}{(x+3)(x-2)}-\dfrac{1}{x-2} \\ =\dfrac{(x+2)(x-2)-5-(x+3)}{(x+3)(x-2)}\\ =\dfrac{x^2-4-5-x-3}{(x+3)(x-2)}\\ =\dfrac{x^2-x-12}{(x+3)(x-2)}\\ =\dfrac{(x^2-4x)+(3x-12)}{(x+3)(x-2)}\\ =\dfrac{x(x-4)+3(x-4)}{(x+3)(x-2)}\\ =\dfrac{(x+3)(x-4)}{(x+3)(x-2)}\\ =\dfrac{x-4}{x-2}\\ b) x^2-9=0\\ \Leftrightarrow x^2=9\\ \Leftrightarrow x= \pm 3\\ \circledast x=-3, C=\dfrac{-3-4}{-3-2}=\dfrac{7}{5}\\ \circledast x=3, C=\dfrac{3-4}{3-2}=-1\\ c) C=-0,75\\ \Leftrightarrow \dfrac{x-4}{x-2}=-0,75\\ \Leftrightarrow x-4=-0,75(x-2)\\ \Leftrightarrow x-4=-0,75x+1,5\\ \Leftrightarrow 1,75x=5,5\\ \Leftrightarrow x=\dfrac{22}{7}\\ d) C=\dfrac{x-4}{x-2}=\dfrac{x-2-2}{x-2}=1-\dfrac{2}{x-2}\\ x \in \mathbb{Z}, C \in \mathbb{Z}\\ \Rightarrow (x-2) \in Ư(2)\\ \Rightarrow (x-2) \in \{-2;-1;1;2\}\\ \Rightarrow x \in \{0;1;3;4\}.$