Respuesta :

Answer:

Below in bold.

Step-by-step explanation:

f(x) = x(18x + 4)

f(x) = 18x^2 + 4x

Antiderivative = 18 * (x^2+1)/(2 + 1) -+4x(1+1) / (1+1) + C

                        =  18x^3 / 3 + 4x^2 / 2 + C

                         = 6x^3 + 2x^2 + C.

Checking by differentiating:

f'(x) = 6*3 x^(3-1) + 2*2x^(2-1)

      =  18x^2 + 4x

      =  x(18 -+4)