(fg)(x)= x³ - 7x² - 9x + 8
domain is (-∞,∞)
Given: f(x)= x-8, g(x)= x² +1x - 1
To find (fg)(x) we multiply f(x) and g(x)
(fg)(x) = f(x) * g(x)
(fg)(x)= (x-8) (x²+x-1)
(fg)(x)= x³ + x² - x - 8x² - 8x +8
(fg)(x)= x³ - 7x² - 9x + 8
we know, domain for all cubic function is set of all real numbers
domain is (-∞,∞)
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