Question

x-2\(\sqrt{x-1}\)-4=0

Answer 1

ĐKXĐ: x>=1

\(x-2\sqrt{x-1}-4=0\)

=>\(x-1-2\sqrt{x-1}-3=0\)

=>\(\left(\sqrt{x-1}\right)^2-2\sqrt{x-1}-3=0\)

=>\(\left(\sqrt{x-1}-3\right)\left(\sqrt{x-1}+1\right)=0\)

=>\(\sqrt{x-1}-3=0\)(Vì \(\sqrt{x-1}+1>=1>0\forall x>=1\))

=>\(\sqrt{x-1}=3\)

=>x-1=9

=>x=10(nhận)