(Original post by Expression)
I agree with Bigcnee to a certain extent here, if it asked you to use a specific method to find the minimum then you will have got 1 mark for finding the minimum as an end result.
If however, the question somewhat spoon fed you:
a) Find the completed square form of f(x)
b) Hence find the minimum value.
Then you may have gotten a few more marks, although where is says hence, it suggests that your answer for a) is a BIG clue in the answer for b) !
lookin at the mark scheme for this, there is only one mark for finding the least value.
therefore, if u put "the lest value for the given quadratic equation is 4", then u get the mark.
therefore, if in doubt, u could always do it by finding the min turnin point, using differentiation (i.e. on scrap paper) then put ur answer down and get all the marks.
or, u cud just do a bit f revision and remember how to find it after completing the square, as expression reminded me.