Question

cứu mọi người ơi

 

Answer 1

a.

\(x=3\Rightarrow B=\dfrac{3}{3+2}=\dfrac{3}{5}\)

b.

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

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

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