`text{C = |6y - 48| - 2008}`
`text{Ta có: |6y - 48| ≥ 0}` $\forall$ `text{y}`
`text{⇒ |6y - 48| - 2008 ≥ -2008}`
`text{⇔ Min C = -2008}`
`text{Dấu "=" xảy ra khi: 6y - 48 = 0}`
`text{ 6y = 48}`
`text{ y = 8}`
`text{Vậy Min C = -2008 khi y = 8}`
`text{________________________}`
`text{B = -x² + 2021}`
`text{Ta có: x² ≥ 0 }`$\forall$ `text{x}`
`text{⇒ -x² ≤ 0}` $\forall$ `text{x}`
`text{⇒ -x² + 2021 ≤ 2021}` $\forall$ `text{x}`
`text{Vậy Max B = 2021}`
`text{Dấu "=" xảy ra khi: -x² = 0}`
`text{ x = 0}`
`text{Vậy Max B = 2021 khi x = 0}`
