Let's use the variable x to represent the price of the television set before taxes.
If the tax rate is 4%, then the original price is multiplied by 1.04, so it is equal 1.04x.
The final price is $520, so we have:
[tex]\begin{gathered} 1.04x=520 \\ x=\frac{520}{1.04} \\ x=500 \end{gathered}[/tex]So the price before taxes is $500.00.