Let's write this in fractions. I don't like decimals. Just a thing.
\(\displaystyle \L\\\frac{x}{\frac{3}{10}}=\frac{10x}{3}\)
and \(\displaystyle 6.28=\frac{157}{25}\)
So, we have \(\displaystyle \L\\\frac{10x}{3}=4x+\frac{157}{25}\)
Subtract 4x from both sides:
\(\displaystyle \L\\\frac{-2x}{3}=\frac{157}{25}\)
Now, can you solve for x?.