Question

giúp em câu 1

Answer 1

Câu 1: 

a \(P=\left(\dfrac{3}{2x+4}+\dfrac{x}{2-x}+\dfrac{2x^2+3}{\left(x-2\right)\left(x+2\right)}\right):\dfrac{2x-1}{4x-8}\)

\(=\left(\dfrac{3}{2\left(x+2\right)}-\dfrac{x}{x-2}+\dfrac{2x^2+3}{\left(x-2\right)\left(x+2\right)}\right)\cdot\dfrac{4\left(x-2\right)}{2x-1}\)

\(=\dfrac{3x-6-2x^2-4x+4x^2+6}{2\left(x-2\right)\left(x+2\right)}\cdot\dfrac{4\left(x-2\right)}{2x-1}\)

\(=\dfrac{2x^2-x}{x+2}\cdot\dfrac{2}{2x-1}=\dfrac{2x}{x+2}\)

b: =>(2x-1)(2x+1)=0

=>x=1/2(loại) hoặc x=-1/2(nhận)

KHi x=-1/2 thì \(A=\dfrac{2\cdot\dfrac{-1}{2}}{-\dfrac{1}{2}+2}=-1:\dfrac{3}{2}=-\dfrac{2}{3}\)