Question

Cho A = (1 - 4/ √x + 1 +1/ x+1 ). x-2√x / x-1

Với x > 0 , x khác 4

a, rut gon A

b, Tìm x để A = 1/2

Answer 1

đề bài là như vậy hả ???

\(\left(\dfrac{1-4}{\sqrt{x}-1}+\dfrac{1}{x+1}\right).\dfrac{x-2\sqrt{x}}{x-1}\)

Answer 2

a:\(A=\left(1-\dfrac{4}{\sqrt{x}+1}+\dfrac{1}{x-1}\right):\dfrac{x-2\sqrt{x}}{x-1}\)

\(=\dfrac{x-1-4\sqrt{x}+4+1}{x-1}\cdot\dfrac{x-1}{x-2\sqrt{x}}\)

\(=\dfrac{\sqrt{x}-2}{\sqrt{x}}\)

b: Để A=1/2 thì \(\dfrac{\sqrt{x}-2}{\sqrt{x}}=\dfrac{1}{2}\)

=>2 căn x-4=căn x

=>x=16