ok, apply product rule on right side, you'll still get the same ans.

you have x*ln3.

diff it as per product rule:  x*(d(ln3)/dx) + ln3 (dx/dx)

As, ln3 is a constant. So, it's diff. will be zero.

So, we are left with ln3 only.

Hope it's clear now.

Feel free to ask/nudge.