Calculus 8th Edition

$f'(x) = -10x + 8$ Domain: All Real Numbers
$f(x) = 4 + 8x - 5x^{2}$ $f'(x) = 8x^{1-1} - (2)5x^{2-1}$ $f'(x) = -10x + 8$ Domain is all real numbers because there values of x that would make f'(x) undefined