You have the following expression:
f(x) = (x - 2)² + 6
in order to write the previous expression in standard form, expand the squared term and simplify, as follow:
(x - 2)² = x² - 2(x)(2) + 2² = x² - 4x + 4
then, into the expression for f(x) you obtain:
f(x) = x² - 4x + 4 + 6 simplify like terms
f(x) = x² - 4x + 10
Hence, the standard form of the given expression is x² - 4x + 10