Question

Answer 1

23: ĐKXĐ: x>=3

\(\sqrt{4x-12}+\dfrac{1}{3}\cdot\sqrt{9x-27}=4+\sqrt{x-3}\)

=>\(2\sqrt{x-3}+\dfrac{1}{3}\cdot3\sqrt{x-3}=4+\sqrt{x-3}\)

=>\(2\sqrt{x-3}=4\)

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

=>x-3=4

=>x=4+3=7(nhận)

25: ĐKXĐ: x>=4

\(5\sqrt{4x-16}-\dfrac{7}{3}\cdot\sqrt{9x-36}=36-3\sqrt{x-4}\)

=>\(5\cdot2\sqrt{x-4}-\dfrac{7}{3}\cdot3\sqrt{x-4}=36-3\sqrt{x-4}\)

=>\(10\sqrt{x-4}-7\sqrt{x-4}+3\sqrt{x-4}=36\)

=>\(6\sqrt{x-4}=36\)

=>\(\sqrt{x-4}=6\)

=>x-4=36

=>x=36+4=40(nhận)

27: ĐKXĐ: x>=5

\(\sqrt{4x-20}+\sqrt{x-5}=4+3\cdot\sqrt{\dfrac{x-5}{9}}\)

=>\(2\sqrt{x-5}+\sqrt{x-5}=4+3\cdot\dfrac{\sqrt{x-5}}{3}\)

=>\(2\sqrt{x-5}=4\)

=>\(\sqrt{x-5}=2\)

=>x-5=4

=>x=4+5=9(nhận)