how do I get
But "how do I get" an equation usually means "how do I show that these are the same for all x". And what you have isn't. For example if x=3, the left side (of both of those) is while the right side of the last is , NOT 2. For the first, it is 1/3- 1= -2/3.
If you mean "how do I solve ?} the simplest thing to do is get rid of the square roots by squaring both sides: which, mutiplying both sides by gives so you have to solve the cubic equation . However, that has no rational number roots so I doubt if that is what you mean.