Calculate dy/dx if y = ln (2x3 + 3x).

Differentiate using the chain rule:

d/du [ln(u)] d/dx[2x^3+3x]

derivative of ln(u) = 1/u

1/u d/dx[2x^3+3x]

1/2x^3+3x d/dx[2x^3+3x]

Differentiate

(6x^2+3) 1/2x^3+3x

Simplify

Dy/dx = 3(2x^2+1) / x(2x^2 +3)

So don't take my word i'm not exactly a mathematical person but i would assume a. because while selling the soap every month you increase in sells so you would by 11 percent. the you would get the factor 0.89 which if i had to guess would be the monthly profit over 11 probably wrong tho