Question 756196
Assuming you meant to write:

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


then


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


{{{
(x-3)^2-(x-3)=0
}}}


{{{
(x-3)(x-3+1)=0
}}}


so that x=3 or x=4 (extraneous)


:)