+33661 Take logs of both sides
log(3x) = log(49)
x*log(3) = log(49)
x = log(49)/log(3)
$${\mathtt{x}} = {\frac{{log}_{10}\left({\mathtt{49}}\right)}{{log}_{10}\left({\mathtt{3}}\right)}} \Rightarrow {\mathtt{x}} = {\mathtt{3.542\: \!487\: \!498\: \!322\: \!844\: \!4}}$$
