Using the completing-the-square method, rewrite f(x) = x2 − 6x + 2 in vertex form.
a. f(x) = (x-3)^2
b. f(x) = (x-3)^2 + 2
c. f(x) = (x-3)^2 - 7
d. f(x) = (x-3)^2 + 9