14:
a: =>căn x-1+1=2
=>căn x-1=1
=>x-1=1
=>x=2
b: =>\(\left(\dfrac{2x}{1-\sqrt{2x+1}}\right)^2=2x+6\)
=>\(\left(\dfrac{2x+1-1}{\sqrt{2x+1}-1}\right)^2=2x+6\)
=>(căn 2x+1+1)^2=2x+6
=>2x+1+1+2*căn 2x+1=2x+6
=>2*căn(2x+1)=2x+6-2x-2=4
=.căn 2x+1=2
=>2x+1=4
=>2x=3
=>x=3/2
c: =>\(\left(\dfrac{x}{\sqrt{x+1}+1}\right)^2=x-4\)
=>\(\left(\sqrt{x+1}-1\right)^2=x-4\)
=>\(x+1+1-2\sqrt{x+1}=x-4\)
=>2căn (x+1)=x+2-x+4=6
=>x+1=9
=>x=8