Answer
-3, 3, -4
Work Step by Step
(x^2-9)(x^2+8x+16)=0
let each part equal to zero separately:
(x^2-9)=0
(x^2+8x+16)=0
Lets do the first part first
(x^2-9)=0
Since it is difference of squares then it can be written as
(x-3)(x+3)=0
x-3=0 x=3
x+3=0 x=-3
Then let's do the second part
(x^2+8x+16)=0
Using ac method ac=16 b= 8
Two numbers are 4 and 4 then
(x^2+4x+4x+16)=0
x(x+4)+4(x+4)=0
(x+4)(x+4)=0
Since this is double root solving either pair give the same answer
x+4=0 x=-4
