B is the right answer for this
when you simplify this you get 1/16x^8
X^2 - 7x + 12 = 0
x^2 - 4x - 3x + 12 = 0
x (x - 4) -3 ( x - 4) = 0
(x - 4) (x - 3) = 0
x = 3 , 4
Check the answer by plugging in 3 and 4 for x, if the equation equals zero then you have your answer.
( - ∞, 3) ∪ (3, ∞ )
The domain is the set of values of x which make f(x) defined
The denominator of f(x) cannot be zero as this would make f(x) undefined. Equating the denominator to zero and solving gives the value that x cannot be.
solve x - 3 = 0 ⇒ x = 3
domain : (- ∞, 3) ∪ (3, ∞ )