Write the following quadratics in the form y=(x−h)2+k by "completing the square". Hence sketch each function, stating the coordinates of the vertex.
a. a $y = x^2 - 2x + 3
b. b $y = x^2 + 4x - 2
c. c $y = x^2 - 4x
d. d $y = x^2 + 3x
e. e $y = x^2 + 5x - 2
f. f $y = x^2 - 3x + 2
g. g $y = x^2 - 6x + 5
h. h $y = x^2 + 8x - 2
i. i $y = x^2 - 5x + 1