9514 1404 393
Answer:
12
Step-by-step explanation:
The square can be completed by adding and subtracting the square of half the linear term's coefficient.
f(x) = x^2 -8x +(-8/2)^2 +28 -(-8/2)^2
f(x) = (x^2 -8x +16) +(28 -16)
f(x) = (x -4)^2 +12
The minimum value of the function is 12, when the squared term is zero.
