Question

square root of (2x+3)-x= 0

Answer 1

start with
\[\sqrt{2x+3}=x\] the square both sides to get
\[2x+3=x^2\] the
\[x^2-2x-3=0\]
\[(x-3)(x+1)=0\] so
\[x=3\text{ or } x=-1\] then check both answers

Answer 2

you will see that 3 works, but -1 does not