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