Complete the square for the quadratic expression x^2 − 8x + 7
As the coefficient (the number before) of x2 is 1 we can start the expression with (x...The coefficient of x is -8 so we half this to complete the brackets and form (x-4)2...Next the square of -4 is subtracted as this will form a remainder when the brackets are expanded (x-4)2-16Finally 7 is added to the expression to form (x-4)2-9
