Question

Cho biểu thức A=\(\dfrac{4}{3x-6}\)- \(\dfrac{x}{x^2-4}\)

Rút gọn A

Answer 1

\(A=\dfrac{4}{3x-6}-\dfrac{x}{x^2-4}\)

\(\Leftrightarrow A=\dfrac{4}{3\left(x-2\right)}-\dfrac{x}{\left(x+2\right)\left(x-2\right)}\)

\(\Leftrightarrow A=\dfrac{4x+8}{3\left(x+2\right)\left(x-2\right)}-\dfrac{3x}{3\left(x+2\right)\left(x-2\right)}\)

\(\Leftrightarrow A=\dfrac{4x+8-3x}{3\left(x+2\right)\left(x-2\right)}\)

\(\Leftrightarrow A=\dfrac{x+8}{3\left(x+2\right)\left(x-2\right)}\)

Answer 2

A=\(\dfrac{4}{3x-6}\)- \(\dfrac{x}{x^2-4}\)

<=> \(\dfrac{4}{3\left(x-2\right)}\)-\(\dfrac{x}{\left(x-2\right)\left(x+2\right)}\)

<=> \(\dfrac{4\left(x+2\right)-3x}{3\left(x-2\right)\left(x+2\right)}\)

<=>\(\dfrac{4x+8-3x}{3\left(x-2\right)\left(x+2\right)}\)

<=> \(\dfrac{x+8}{3\left(x-2\right)\left(x+2\right)}\)