need help :'( i have to find the intervals in which f(x)=-2x³-9x²-12x+1 are strictly increasing or decreasing having problem with finding the value of x f'(x)0 -6x²-18x-120 -x²-3x-20 x²+3x+2

Question

need help :'( i have to find the intervals in which f(x)=-2x³-9x²-12x+1 are strictly increasing or decreasing having problem with finding the value of x f'(x)>0 -6x²-18x-12>0 -x²-3x-2>0 x²+3x+2<0 x²+2x+x+2<0 (x+2)(x+1)<0 having problem after this part :'( my answer x<-2 and x<-1 which is wrong can u help me out

anonymous · Answer

http://www.flickr.com/photos/83749253 @N08/9267437643/sizes/k/in/photostream/ :'(

anonymous · Answer

http://www.flickr.com/photos/83749253 @N08/9267437643/sizes/k/in/photostream/

loser66 · Answer

attachment

loser66 · Answer

I don't know whether my way makes sense to you or not. That's what I was taught

anonymous · Answer

@Loser66 -oh :OO havenot see that method before seems like that method is cool :D