Bài 1:
a: Thay x=3 vào B, ta được:
\(B=\dfrac{3-2}{3^2-3}=\dfrac{1}{6}\)
b: \(P=\dfrac{x+2}{x}+\dfrac{x+5}{x-1}-\dfrac{x-2}{x\left(x-1\right)}\)
\(=\dfrac{x^2+x-2+x^2+5x-x+2}{x\left(x-1\right)}=\dfrac{2x^2+5x}{x\left(x-1\right)}=\dfrac{2x+5}{x-1}\)
c: Để P=13/3 thì 6x+15=13x-13
=>-7x=-28
hay x=4