I am guessing that you are looking for the domain of the function.
f(x) = √(4x2-19x+12)
domain = {x l 4x2 - 19x +12 ≥ 0]
= {x l (4x-3)(x-4) ≥ 0}
(4x-3)(x-4) = 0 when x = 3/4 or x = 4
When x < 3/4, (4x-3)(x-4) > 0
When 3/4<x<4, (4x-3)(x-4) < 0
When x>4, (4x-3)(x-4) > 0
Domain: (-∞, 3/4] ∪ [4,∞)
Arturo O.
02/23/17