Question 62763
Given a equation f(x) = x (x+3) (x-1)

For x = 0 the functionf(x) = 0, 
It contradicts the condition f(x) > 0

For x =1, the function f(x)= 0
But it contradicts the condition f(x)> 0

for x =2, f(x) = 10

The condition f(x)>0 its been satisfied.

We construct the interval (1,+infinty)

Let us now consider for x = -1,
the function f(x) =4

The condition for f(X) > 0 is satisfied.

for x =-2, f(x) = 6
It satisfies f(x) > 0

For x =-3, f(x) = 0
Which contradicts the condition f(x) > 0
Therefore all the values from -1 to -2 is satisfied.
We construct the interval(-2 ,-1)

The values of "x" in interval notation can be written as
[-2, -1] U [2, infinity]