This looks like a complicated problem but it is actually a very simple problem, if you know the process for solving it. Let us now get down to solving the problem in hand.
log6(2x + 3) = 3
6^3 = 2x + 3
216 = 2x + 3
2x = 216 - 3
2x = 213
x = 106.5
I hope that the procedure is clear enough for you to understand and this is the answer that you were looking for and the answer has actually come to your desired help.