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2(x+3)^3(x+2)^3(x-2)^2>0

User Letronje
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1 Answer

3 votes
First observe that the left hand side evaluates to 0 whenever
x=-3,
x=-2, or
x=2.

So let's take numbers to either side of these roots. If
x=-4, for instance, we have
(-4+3)^3=(-1)^3=-1<0,
(-4+2)^3=(-2)^3=-8<0, and
(-4-2)^2=(-6)^2=36>0. We would be multiplying a positive number (2) by two negatives (-1 and -8) and a positive (36), which gives a positive number. So, we know
x<-3 must be a solution set.

Doing the same for numbers between/beyond the other three cases,
-3<x<-2,
-2<x<2, and
x>2, we would get, respectively, a negative, positive, and a positive.

The entire solution set would then be the union of the intervals over which we get a positive number, i.e.
(x<-3)\cup(-2<x<2)\cup(2<x)
User Cmeeren
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