Determine the x values that cause the polynomial function to be positive:
f(x)=(x+2)(x+1)(x-5) determine the x values that cause the polynomial function to be positive:
f(x)=(x+2)(x+1)(x-5)

So here is how you determine the values of x that cause the polynomial function to be positive. 
Set each one greater than zero:x+2>0x+1>0x−5>0

Then, solve for x on all three:
 x > -2 x > -1 x > 5
 so in order for the polynomial to be positive the answer is x > 5.
Hope this is the answer that you are looking for.