Question

Rút gọn biểu thức

Answer 1

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

\(=\dfrac{x}{x^2+x+1}\)

d: \(=\dfrac{x^2-7+x-3-x+1}{\left(x-3\right)\left(x-1\right)}=\dfrac{x^2-9}{\left(x-3\right)\left(x-1\right)}=\dfrac{x+3}{x-1}\)

Answer 2

c, đk x khác 1 

\(=\dfrac{x^2+2+\left(x^2-1\right)-x^2-x-1}{x^3-1}=\dfrac{x^2-x}{x^3-1}=\dfrac{x}{x^2+x+1}\)

d, đk x khác 1 ; 3 

\(=\dfrac{x^2-7+x-3-x+1}{\left(x-1\right)\left(x-3\right)}=\dfrac{x^2-9}{\left(x-1\right)\left(x-3\right)}=\dfrac{x+3}{x-1}\)