For the inequality:
x^2 - 5x
+6 > 0
First we will
factor:
==> (x-2)(x-3) >
0
Now we have a product of two function. In order for the
product of two numbers to be positive ( > 0) then both numbers should be positive
or both numbers should be negative.
Then we have two
options:
(x-2) > 0 AND x-3 >
0
We will solve.
==> x
> 2 AND x > 3
==> x = (2, inf) n (
3, inf) = (3,in)
==> x = (3, inf )
............(1)
For the second
option:
(x-2) < 0 AND (x-3) <
0
==> x < 2 AND x <
3
==> x = (-inf , 2) n (-inf, 3) = (-inf,
2)
==> x = (-inf, 2)
.............(2)
Then, we have two possible
solutions: (1) and (2).
==> x = (-inf
, 2) U ( 3, inf)
OR: x <2 OR x
> 3
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