[tex]\it d)\ x^2-x+1=x^2-x+\dfrac{1}{4}+\dfrac{3}{4}=(x-\dfrac{1}{2})^2 +\dfrac{3}{4}\\ \\ pentru \ \ x=\dfrac{1}{2} \Rightarrow valoarea\ minim\breve a=\dfrac{3}{4}[/tex]
