s(x)=log3(x^2+6x) find derivative?

Answer 1

if u = f(x)
and y = g(u)

dy/dx = dy/du * du/dx

y = log3(u)
u = x^2 + 6x

dy/dx = 1/ln3 * 1/u * du/dx
= 1/ln3 * 1/(x^2 + 6x) * (2x+6)
= (2x+6)/(ln 3 * (x^2 + 6x))