Question 66981
Stanbon forgot to CHECK the answers!  Whenever you square both sides of an equation, you must check the answers to see if they really work according to the Principle Value Definition of Square Root.  In this case, the answer of x=9 works, but x=1 results in {{{sqrt(9)+4= 1}}}, (where {{{sqrt(9) = 3}}} by Principle Value Definition) which is NOT true, so it must be rejected as an extraneous root!  The solution is ONLY x=9.


R^2 at SCC