Answer:
(-∞,-9) U (2,3)
Step-by-step explanation:
(x+9)(x²-5x+6) < 0
x²-5x +6
= x² -3x -2x +6
= x( x-3) -2(x-3)
= (x-3)(x-2)
Substituting
(x+9)(x-2)(x-3)
For x < -9
the term is negative
For x >-9 x<2
the term is positive
For x>2 x<3
the term is negative
For x>3
the term is positive
(x+9)(x-2)(x-3) < 0
(-∞,-9) U (2,3)