Rút gọn các biểu thức sau: a) 2/ 3x + x/ x-1+ 6x^2-4/ 2x( 1-x);

Trả lời

a) $$\begin{gathered} \frac{2}{3x}+\frac{x}{x-1}+\frac{6x^2-4}{2x(1-x)}=\frac{2}{3x}-\frac{x}{1-x}+\frac{2(3x^2-2)}{2x(1-x)}=\frac{2}{3x}-\frac{x}{1-x}+\frac{3x^2-2}{x(1-x)} \\ =\frac{2(1-x)-x.3x+3(3x^2-2)}{3x(1-x)}=\frac{2-2x-3x^2+9x^2-6}{3x(1-x)} \\ =\frac{{\displaystyle 6x^2-2x-4}}{{\displaystyle 3x(1-x)}} \end{gathered}$$