(i) f(x) = ln (x – 5)
f is defined, when x – 5 > 0
∴ x > 5
∴ Domain of f = (5, ∞)
(ii) f(x) = log10 (x2 – 5x + 6)
x2 – 5x + 6 = (x – 2) (x – 3)
f is defined, when (x – 2) (x – 3) > 0
∴ x < 2 or x > 3
Solution of (x – a) (x – b) > 0 is x < a or x > b
where a < b
∴ Domain of f = (-∞, 2) ∪ (3, ∞)
