Step-by-step explanation:
The domain of the rational expression is when the denominator is defined. (non-zero)
When the denominator is 0,
4x² - 4 = 0.
=> x² - 1 = 0, (x + 1)(x - 1) = 0, x = -1 or x = 1.
Hence the answer is all real numbers except x = -1 and x = 1.
