e)
`P = 18 - |2x - 3| - |y + 3/5|`
`|2x - 3| <= 0`
`|y + 3/5| <=0`
Ta có:
`8 - |2x - 3| - |y + 3/5| <= 18-0`
`=> Pmax = 18-0 =18`
Dấu "=" xảy ra khi:
`<=>` $\left[\begin{matrix} 2x-3=0\\ y + \dfrac{3}{5} = 0\end{matrix}\right.$
`<=>` $\left[\begin{matrix} 2x=-3\\ y =- \dfrac{3}{5}\end{matrix}\right.$
`<=>` $\left[\begin{matrix} x =\dfrac{3}{2}\\ y =- \dfrac{3}{5}\end{matrix}\right.$
Vậy `GTLN` của `Pmax = 18 <=>` $\left[\begin{matrix} x =\dfrac{3}{2}\\ y =- \dfrac{3}{5}\end{matrix}\right.$
