Question

Answer 1

b: \(\left(x+1\right)\left(x^2+x+1\right)>=0\)

mà \(x^2+x+1=\left(x+\dfrac{1}{2}\right)^2+\dfrac{3}{4}>=\dfrac{3}{4}>0\forall x\)

nên x+1>=0

=>x>=-1

c: \(\left(2x-3\right)\left(x^2-2x+3\right)< 0\)

mà \(x^2-2x+3=\left(x-1\right)^2+2>=2>0\forall x\)

nên 2x-3<0

=>2x<3

=>\(x< \dfrac{3}{2}\)