Answer:
see explanation
Step-by-step explanation:
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← factor the denominators
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← simplify numerator
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The denominator cannot be zero as this would make the rational function undefined
Equating the denominator to zero and solving gives the values of x that cannot be in the domain
5(x + 2)(x - 4) = 0
Equate each factor to zero and solve for x
x + 2 = 0 ⇒ x = - 2
x - 4 = 0 ⇒ x = 4
x = - 2, x = 4 ← excluded values
domain : x ∈ R ( x ≠ - 2, x ≠ 4 )