Question

Answer 1

Câu 8:

a: ĐKXĐ: x>=-5

\(\sqrt{4x+20}+\sqrt{x+5}-\dfrac{1}{3}\cdot\sqrt{9x+45}=4\)

=>\(2\sqrt{x+5}+\sqrt{x+5}-\dfrac{1}{3}\cdot3\sqrt{x+5}=4\)

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

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

=>x+5=4

=>x=4-5=-1(nhận)

b: ĐKXĐ: x>=0

\(\dfrac{2\sqrt{x}-7}{3}+\sqrt{x}-\dfrac{3\sqrt{x}-5}{2}=1\)

=>\(\dfrac{2}{3}\sqrt{x}-\dfrac{7}{3}+\sqrt{x}-\dfrac{3}{2}\sqrt{x}+\dfrac{5}{2}=1\)

=>\(\dfrac{1}{6}\sqrt{x}=1+\dfrac{7}{3}-\dfrac{5}{2}=\dfrac{5}{6}\)

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

=>x=25(nhận)