Question 973075
Even without solving, a sense that x-3 is 0 or 1.

{{{sqrt(x-3)=x-3}}}


{{{x-3=(x-3)^2}}}


{{{x-3=x^2-6x+9}}}


{{{x^2-6x-x+9+3=0}}}


{{{x^2-7x+12=0}}}


{{{(x-3)(x-4)=0}}}


Indicated solutions are 3 or 4.
Both are acceptable inputs for {{{sqrt(x-3)}}}.
These two input values for x also are in perfect agreement with the initial guess about x-3 and sqrt(x-3).  You can use the found solutions to check this.