(x+20)(x-9)(x+10)>0

Question

Please help? I'm stuck...need to find the solution set.

so far I have
x^3+21x^2-70x-1800>0
am I correct so far?
What do I need to do next?

Answer 1

-20<-10<x<9
is this correct?

Answer 2

Why did you reverse the carat for all the values? That should only happen when multiplying/dividing by a negative number.

x>9
x>-10
x>-20