X =26 I know it’s not on the but that’s the right answer
The letter "x" is often used in algebra to mean a value that is not yet known. It is called a "variable" or sometimes an "unknown". In x + 2 = 7, x is a variable, but we can work out its value if we try!
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
