x+23log(1+e−3x)+Cx+\frac{2}{3} \log \left(1+e^{-3 x}\right)+Cx+32log(1+e−3x)+C
x+23(1+e−3x)x+\frac{2}{3}\left(1+e^{-3 x}\right)x+32(1+e−3x)
x+2log(1+e−3x)+Cx+2 \log \left(1+e^{-3 x}\right)+Cx+2log(1+e−3x)+C
x−23(1+e−3x)+Cx-\frac{2}{3}\left(1+e^{-3 x}\right)+Cx−32(1+e−3x)+C