Question

Answer 1

a: ĐKXĐ: x<>0; x<>1

\(P=\dfrac{x^2-1+2+x-x^2}{x\left(x-1\right)}:\dfrac{x^2+x+1-x^2}{\left(x-1\right)\left(x^2+x+1\right)}\)

\(=\dfrac{x+1}{x\left(x-1\right)}\cdot\dfrac{\left(x-1\right)\left(x^2+x+1\right)}{x+1}=\dfrac{x^2+x+1}{x}\)

b: P=3x

=>3x^2=x^2+x+1

=>2x^2-x-1=0

=>(x-1)(2x+1)=0

=>x=1(loại) hoặc x=-1/2(nhận)

c: \(P-3=\dfrac{x^2-2x+1}{x}=\dfrac{\left(x-1\right)^2}{x}>0\)

=>P>3