Question

Cho P=\(\dfrac{2x}{x+3}\)(x≠-3;x≠1).Tính giá trị của P biết

A.x=6                                b.|x-2|=1

Answer 1

b) \(\left|x-2\right|=1\)

\(\Leftrightarrow\left[{}\begin{matrix}x-2=1\\x-2=-1\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=3\\x=1\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}P=\dfrac{2.3}{3+3}=1\left(x=3\right)\\P=\dfrac{2.1}{1+3}=\dfrac{2}{4}=\dfrac{1}{2}\left(x=1\right)\end{matrix}\right.\)

Answer 2

a: Khi x=6 thì \(P=\dfrac{2\cdot6}{6+3}=\dfrac{12}{9}=\dfrac{4}{3}\)

b: |x-2|=1

=>x-2=1 hoặc x-2=-1

=>x=1(loại) hoặc x=3(nhận)

Khi x=3 thì \(P=\dfrac{2\cdot3}{3+3}=\dfrac{6}{6}=1\)