Question

Cho \(x\ge2\). Cmr: \(x+\dfrac{1}{2}\ge\dfrac{5}{2}\)

Giúp mik nha mik đang cần gấp lắm!!!

Answer 1

Từ \(x\ge2\) cộng cả hai vế với \(\dfrac{1}{2}\) ta được

\(x+\dfrac{1}{2}\ge2+\dfrac{1}{2}=\dfrac{5}{2}\)

Answer 2

\(VT=x+\dfrac{1}{2}=x-2+2+\dfrac{1}{2}=\left(x-2\right)+\dfrac{5}{2}\)

\(\left\{{}\begin{matrix}x\ge2\Rightarrow x-2\ge0\\VT=\left(x-2\right)+\dfrac{5}{2}\ge\dfrac{5}{2}=VP\rightarrow dpcm\end{matrix}\right.\)