2:
a: \(A=\left(\dfrac{2x+1}{2\left(x+2\right)}-\dfrac{x}{3\left(x-2\right)}-\dfrac{2x^2}{3\left(x-2\right)\left(x+2\right)}\right)\cdot\dfrac{-12\left(x-2\right)}{13x+6}\)
\(=\left(\dfrac{\left(3x-6\right)\left(2x+1\right)-2x\left(x+2\right)-4x^2}{6\left(x-2\right)\left(x+2\right)}\right)\cdot\dfrac{-12\left(x-2\right)}{13x+6}\)
\(=\dfrac{6x^2+3x-12x-6-2x^2-4x-4x^2}{x+2}\cdot\dfrac{-2}{13x+6}\)
\(=\dfrac{-13x-6}{x+2}\cdot\dfrac{-2}{13x+6}=\dfrac{2}{x+2}\)
b: A>0
=>x+2>0
=>x>-2
c: |2x-1|=3
=>x=2(loại) hoặc x=-1(nhận)
Khi x=-1 thì \(A=\dfrac{2}{-1+2}=2\)
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