Question

Giúp em với ạ em cảm ơn

Answer 1

Câu 1: 

1: \(A=\left(\dfrac{\sqrt{x}}{\sqrt{x}-2}-\dfrac{5\sqrt{x}-4}{x-\sqrt{x}-2}\right):\dfrac{\sqrt{x}+1-3}{\sqrt{x}+1}\)

\(=\dfrac{\sqrt{x}\left(\sqrt{x}+1\right)-5\sqrt{x}+4}{\left(\sqrt{x}-2\right)\left(\sqrt{x}+1\right)}\cdot\dfrac{\sqrt{x}+1}{\sqrt{x}-2}\)

\(=\dfrac{x+\sqrt{x}-5\sqrt{x}+4}{\left(\sqrt{x}-2\right)^2}\cdot1=1\)

2: Thay x=2a-1 và y=4a-2 vào hàm số, ta được:

\(\left(4a-2\right)=-2\left(2a-1\right)^2\)

\(\Leftrightarrow4a-2+2\left(4a^2-4a+1\right)=0\)

\(\Leftrightarrow4a-2+8a^2-8a+2=0\)

\(\Leftrightarrow8a^2-4a=0\)

=>4a(2a-1)=0

hay \(a\in\left\{0;\dfrac{1}{2}\right\}\)