Final answer:
The nonpermissible replacement for x in the expression x² - 4x + 8 is none. The expression is defined for all real numbers.
Step-by-step explanation:
To find the nonpermissible replacement for x in the expression x² - 4x + 8, we need to determine the values of x that make the expression undefined.
In this case, there are no such values that make the expression undefined. The expression x² - 4x + 8 is defined for all real numbers.