\[ \int \frac {-12+e^x \left (-3-3 x-x^2\right )+\left (e^{3 x} \left (6 x+2 x^2\right )+e^{2 x} \left (24 x+8 x^2\right )\right ) \log \left (\frac {16+4 e^x}{3+x}\right )+\left (e^{3 x} \left (6 x+2 x^2\right )+e^{2 x} \left (24 x+8 x^2\right )\right ) \log \left (\frac {x}{\log (3)}\right )}{\left (12 x+4 x^2+e^x \left (3 x+x^2\right )\right ) \log \left (\frac {16+4 e^x}{3+x}\right )+\left (12 x+4 x^2+e^x \left (3 x+x^2\right )\right ) \log \left (\frac {x}{\log (3)}\right )} \, dx \]
Optimal antiderivative \[ {\mathrm e}^{2 x}-\ln \! \left (\ln \! \left (\frac {x}{\ln \! \left (3\right )}\right )+\ln \! \left (\frac {4 \,{\mathrm e}^{x}+16}{3+x}\right )\right ) \]
command
Integrate[(-12 + E^x*(-3 - 3*x - x^2) + (E^(3*x)*(6*x + 2*x^2) + E^(2*x)*(24*x + 8*x^2))*Log[(16 + 4*E^x)/(3 + x)] + (E^(3*x)*(6*x + 2*x^2) + E^(2*x)*(24*x + 8*x^2))*Log[x/Log[3]])/((12*x + 4*x^2 + E^x*(3*x + x^2))*Log[(16 + 4*E^x)/(3 + x)] + (12*x + 4*x^2 + E^x*(3*x + x^2))*Log[x/Log[3]]),x]
Mathematica 13.1 output
\[ \int \frac {-12+e^x \left (-3-3 x-x^2\right )+\left (e^{3 x} \left (6 x+2 x^2\right )+e^{2 x} \left (24 x+8 x^2\right )\right ) \log \left (\frac {16+4 e^x}{3+x}\right )+\left (e^{3 x} \left (6 x+2 x^2\right )+e^{2 x} \left (24 x+8 x^2\right )\right ) \log \left (\frac {x}{\log (3)}\right )}{\left (12 x+4 x^2+e^x \left (3 x+x^2\right )\right ) \log \left (\frac {16+4 e^x}{3+x}\right )+\left (12 x+4 x^2+e^x \left (3 x+x^2\right )\right ) \log \left (\frac {x}{\log (3)}\right )} \, dx \]
Mathematica 12.3 output
\[ e^{2 x}-\log \left (\log \left (\frac {4+e^x}{3+x}\right )+\log \left (\frac {4 x}{\log (3)}\right )\right ) \]