We may notice that l.h.s. is a strictly increasing function of $x$. Hence there are no roots or there is only one root. We may notice that $x=36$ is a root, hence the answer is $36$.
– Sergei NikolaevSep 18 '22 at 15:23
I don't understand the answer in the general principles of solving radical equations but when I get more time I'll look more into it
– Matthew S.Sep 18 '22 at 15:38