#### Answer

A. $\sqrt 2x = -x$
B. $\ 2x = x^2$
C. $\ x = 2, x = 0$
D. $\ x = 0$

#### Work Step by Step

Letter A asks to isolate the radical, therefore you must subtract the "x" to the other side.
Letter B asks to square both sides. Squaring a radical leaves what's left inside the radical.
For letter C, subtract "2x" to the other side and from there, you will have an equation to solve. "x" will equal 2 and 0.
For letter D, plug in both solutions, however, only 0 will make the statement true.