Answer:
x^3+5x^2+16x+80
Step-by-step explanation:
You know that you can write your polynom this way : (x-r1)(x-r2)(x-r3) with r1,r2 and r3 the roots so you get :
(x+5)(x+4i)(x-4i)
Simplify (x+4i)(x-4i) with the formula (a-b)(a+b)=a²-b²
so you have (x^2+16)=(x+4i)(x-4i)
Your polynom looks like this :
(x^2+16)(x+5) just expand it
and you get x^3+5x^2+16x+80
Answer for the second question:
5*2 is 10
10 *2 is 20
20*2 is 40
40*2 is 80
80 *2 is 160
That's five hours
160*2 is 320
320*2 is 640
640*2 is 1280
1280*2 is 2560
The answer should be 2560
I forgot how to do it with the equation sorry
If you take your calculator and enter in -82+28 it should give you the answer easily If you dont have one use ur phone.
Easiest way 1.o.1
