So I have the following question:

(x+3)^5 (x-1)(x-4)^2 < 0

I know the roots are at -3, 1, 4 and the the intervals are:

(-infinite, -3)

(-3, 1)

(1, 4)

(4, infinity)

However, I don't know how to determine if an interval is positive or negative. Can someone help me? Thanks.