Find the extreme value of the function in the interval, y = 2x ^ 2-8x + 4, X ∈ [1,4]

Find the extreme value of the function in the interval, y = 2x ^ 2-8x + 4, X ∈ [1,4]

It's extremum
y=2x^2-8x+4=2(x²-4x+2)=2(x²-4x+4-4+2)=2(x-2)²-4
2∈〔1,4〕
The extremum of 〈 on 〔 1,4 〕 is - 4