Câu 1:
\(1,ĐK:2016-2017x\ge0\Leftrightarrow x\le\dfrac{2016}{2017}\\ 2,A=6+\sqrt{15}-2\sqrt{15}=6-\sqrt{15}\\ B=\dfrac{12+4\sqrt{5}+12-4\sqrt{5}}{\left(3-\sqrt{5}\right)\left(3+\sqrt{5}\right)}=\dfrac{24}{4}=6\)
Câu 2:
\(\Leftrightarrow x^2+9=9-2x\left(x\le\dfrac{9}{2}\right)\\ \Leftrightarrow x^2+2x=0\Leftrightarrow\left[{}\begin{matrix}x=0\left(tm\right)\\x=-2\left(tm\right)\end{matrix}\right.\)
Câu 3:
\(a,Q=\dfrac{\sqrt{a}-\sqrt{a}+1}{\sqrt{a}\left(\sqrt{a}-1\right)}:\dfrac{a-1-a+4}{\left(\sqrt{a}-1\right)\left(\sqrt{a}-2\right)}=\dfrac{1}{\sqrt{a}\left(\sqrt{a}-1\right)}\cdot\dfrac{\left(\sqrt{a}-1\right)\left(\sqrt{a}-2\right)}{3}\\ Q=\dfrac{\sqrt{a}-2}{3\sqrt{a}}\\ b,Q< 0\Leftrightarrow\sqrt{a}-2< 0\left(3\sqrt{a}>0\right)\\ \Leftrightarrow\sqrt{a}< 2\Leftrightarrow0< a< 4;a\ne1\)
