Quadratic equations - parabolas question ^^

Convert to vertex form [ which is a (x - b)^2 + c ] :-

x^2 + (x + 1)^2

= x^2 + x^2 + 2x + 1

= 2x^2 + 2x + 1

= 2( x*2 + x) + 1

= 2[ (x + 0.5)^2 - 0.25 ] + 1

= 2(x + 0.5)^2 -0.5 + 1

= 2(x + 0.5)^2 + 0.5

The last constant is the minimum value of f(x)

Answer 0.5