Respuesta :

Hrishii

Step-by-step explanation:

[tex]f(x) = {x}^{3} + 5x \\ g(x) = 4x \\ \\ \therefore \: (f.g)(x) = f(x) . g(x) \\ = ( {x}^{3} + 5x ).4x \\ = {x}^{3} .4x + 5x.4x \\ \red{{ \boxed{\bold{\therefore \: (f.g)(x) = 4 {x}^{4} + 20 {x}^{2} }}}}[/tex]