Question

a) \(\sqrt{\dfrac{-3}{5-x}}\) 

b) \(\sqrt{\dfrac{4}{1-x}}\)

c) \(\sqrt{\dfrac{1}{x^2}}\)

Answer 1

a)đk:`(-3)/(5-x)>=0(x ne 5)`

Mà `-3<0`

`=>5-x<0`

`<=>x>5`.

b)đk:`4/(1-x)>=0(x ne 1)`

Mà `4>0`

`=>1-x>0`

`<=>x<1`

c)đk:`1/x^2>0`

1>0

`=>x^2>0`

`=>x ne 0`

Answer 2

a) ĐKXĐ: \(5-x< 0\)

\(\Leftrightarrow x>5\)

b) ĐKXĐ: \(1-x>0\)

\(\Leftrightarrow x>1\)

c) ĐKXĐ: \(x^2>0\)

\(\Leftrightarrow x\ne0\)