Question #9685a

1 Answer
Nov 10, 2017

We don't have to look at the #(x-7)^2# as this will always be #>=0#
Of course #x!=7#

Explanation:

For #AxxB<0# one of them must be #<0# and the other #>0#

(a) #x+2<0->x<-2#
This will make #x-9<-2-9or x-9<-11#. Now both are negative. This will not work.

(b) #x-9<0->x<9#
Remember #x> -2# or we are in situation (a)

Conclusion:
#x<9andx> -2# or in short: # -2 < x<9#, but #x!=7#
graph{(x+2)(x-7)^2(x-9) [-34.98, 38.12, -31.26, 5.3]}