Use completing the square to find the minimum of y = x^2 - 4x + 8

Remember completing the square gives a result of the form (x+q)² + p where q and p are numbers
Also q is always half of the x term, which in this case is -4, as such q = -2
Substituting this in, we get (x-2)² which expands to x² - 4x + 4. To make this equal to our original equation, we need to add 4, getting us y = (x-2)² + 4.
As a rule, the minimum point is always x = -q, y = p. Therefore our answer is (2,4)