Question

Найдите производную функцию.
f(x) = (x + 5)(x − 4)​

Answer 1

$f(x) = (x+5)(x-4) \\\\f'(x) = \dfrac{d}{dx}((x+5)(x-4)) \\\\f'(x) = \dfrac{d}{dx}(x^2-4x+5x-20) \\\\f'(x) = \dfrac{d}{dx}(x^2+x-20) \\\\f'(x) = \dfrac{d}{dx}(x^2) + \dfrac{d}{dx}(x) - \dfrac{d}{dx}(20) \\\\f'(x) = 2x+1 = 0$