Answer:
(fg)(x)= x^3 -7x^2 -9x +8
domain is (-∞,∞)
Step-by-step explanation:
f(x)= x-8
g(x)= x^2 +1x -1
To find (fg)(x) we multiply f(x) and g(x)
(fg)(x) = f(x) * g(x)
(fg)(x)= (x-8) (x^2+x-1)
Multiply x with x^2 +x-1
x^3 +x^2 - x
multiply -8 with x^2 +x -1
-8x^2 -8x+8
(fg)(x)= (x-8) (x^2+x-1)
(fg)(x)= x^3 + x^2 -x -8x^2 -8x +8
combine like terms
(fg)(x)= x^3 -7x^2 -9x +8
Domain of all cubic function is set of all real numbers
domain is (-∞,∞)
