Aloha :)
$$\left.\frac{\sqrt{4x}}{\sqrt9}=\frac{x}{3}\quad\right|\,\text{beide Seiten quadrieren}$$$$\left.\frac{4x}{9}=\frac{x^2}{9}\quad\right|\,\cdot9$$$$\left.4x=x^2\quad\right|\,-4x$$$$\left.x^2-4x=0\quad\right|\,x \text{ ausklammern}$$$$\left.x(x-4)=0\quad\right.$$$$\left.\underline{x=0\;\;\lor\;\;x=4}\quad\right.$$
$$\left.\sqrt{2x}-\sqrt1=x\quad\right|\,\sqrt1=1$$$$\left.\sqrt{2x}-1=x\quad\right|\,+1$$$$\left.\sqrt{2x}=x+1\quad\right|\,\text{beide Seiten quadrieren}$$$$\left.2x=(x+1)^2\quad\right|\;\text{1. binomische Formel rechts}$$$$\left.2x=x^2+2x+1\quad\right|\;-2x$$$$\left.x^2+1=0\quad\right|\;-1$$$$\left.x^2=-1\quad\right.$$$$\left.\underline{x=\{ \}}\quad\right.$$
$$\left.\sqrt{5x}=x\quad\right|\,\text{beide Seiten quadrieren}$$$$\left.5x=x^2\quad\right|\,-5x$$$$\left.x^2-5x=0\quad\right|\,x \text{ ausklammern}$$$$\left.x(x-5)=0\quad\right.$$$$\left.\underline{x=0\;\;\lor\;\;x=5}\quad\right.$$