Answer:
First find f o g (x)
f o g (x) = 1 / x² - 2x
To find the numbers which are not in the domain of f o g equate the denominator to zero
x² - 2x = 0
x(x - 2) = 0
x = 0 and x = 2
The two numbers which are not in the domain of f o g are 0 and 2.
Hope this helps.