Question

Tìm x

a). \(-3x^2\) \(\ge\) 0

b). \(\dfrac{-5}{4x^2}\ge0\)

c). \(\dfrac{4}{x+3}\ge0\)

d). \(\dfrac{-5}{2x-1}\ge0\)

e). \(\dfrac{-2}{x^2+1}\ge0\)

f). \(\dfrac{10}{x^2+9}\ge0\)

Answer 1

 

a: \(-3x^2\ge0\)

\(\Leftrightarrow x^2< =0\)

=>x=0

b: \(\dfrac{-5}{4x^2}\ge0\)

\(\Leftrightarrow4x^2< 0\)(vô lý)

c: \(\dfrac{4}{x+3}>=0\)

=>x+3>0

hay x>-3

d: \(\dfrac{-5}{2x-1}>=0\)

=>2x-1<0

hay x<1/2

e: \(\dfrac{-2}{x^2+1}>=0\)

=>x²+1<0(vô lý)

f: \(\dfrac{10}{x^2+9}>=0\)

=>x²+9>0(luôn đúng)