Radical equation $x- 5\sqrt{x} + 4 = 0$ Solve: Radical equation $x- 5\sqrt{x} + 4 = 0$
I think I understand what I had did wrong. Instead of squaring a product of a number I was squaring the equation. 

$$x-5\sqrt{x}+4=0$$
$$x+4=5\sqrt{x}$$
$$x^2+16+8x=25x$$
$$x^2-17x+16=0$$
$$x_{1,2}=\frac{17\pm\sqrt{17^2-16\cdot 4}}{2}$$
$$x_1=16\qquad;\qquad x_2=1$$
