Giải thích các bước giải:
\(\begin{array}{l}
1)a) = 3\sqrt 3 + 4\sqrt 3 - 6\sqrt 3 - 2\sqrt 3 = \sqrt 3 \\
b)\, = - 7 + 5 - 2\dfrac{2}{3} + \dfrac{1}{3}.3 = - \dfrac{7}{3}\\
2)\,b)\,Thay\,x = 1;y = - 3\,vao\,ham\,so\,ta\,duoc\\
- 3 = \left( {m - 5} \right).1 - 2 \Leftrightarrow m - 7 = - 3 \Leftrightarrow m = 4\\
3)\,A = \left( {\dfrac{{\sqrt x \left( {\sqrt x + 1} \right)}}{{\sqrt x + 1}} + \dfrac{{\sqrt x \left( {\sqrt x - 1} \right)}}{{\sqrt x - 1}}} \right).\left( {\dfrac{{\sqrt x + 1}}{{\sqrt x }}} \right)\\
= \left( {\sqrt x + \sqrt x } \right).\dfrac{{\sqrt x + 1}}{{\sqrt x }} = 2\left( {\sqrt x + 1} \right) = 2\sqrt x + 2\\
b)\, \Leftrightarrow \left\{ \begin{array}{l}
y = - \dfrac{x}{2} + 2\\
y = \dfrac{x}{2} - 2
\end{array} \right.\\
do\, - \dfrac{1}{2} \ne \dfrac{1}{2}\,nen\,he\,pt\,co\,nghiem\,duy\,nhat
\end{array}\)