([tex]\frac{g}{f}[/tex])(x) = [tex]\frac{8}{x+4}[/tex] ÷ [tex]\frac{7}{x}[/tex]
= [tex]\frac{8}{x+4}[/tex] × [tex]\frac{x}{7}[/tex] = [tex]\frac{8x}{7x+28}[/tex]
The denominator cannot be zero as this would make the rational function undefined. Equating the denominator to zero and solving gives the value that x cannot be
solve 7x + 28 = 0 ⇒ x = - 4 ← excluded value
domain is x ∈ (- ∞, - 4 ) ∪ (- 4, + ∞ )
