Question

What are the domain restrictions of the function f(x) = the quantity of x squared plus 6x plus 9, all over 3x plus 15.

Answer 1

x = - 5

Explanation:

Given

f(x) =
`(x^2+6x+9)/(3x+15)`

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 : 3x + 15 = 0 ⇒ 3x = - 15 ⇒ x = - 5 ← excluded value

Domain x ∈ R , x ≠ - 5