To find out how much Emily can spend on the dress before tax, we need to account for the sales tax.
Let \( x \) be the cost of the dress before tax. The sales tax is 5% of the dress cost, which can be expressed as \( 0.05x \). Therefore, the total cost including tax is:
\[ x + 0.05x = 1.05x \]
Since Emily has $30 to spend, we set up the equation:
\[ 1.05x = 30 \]
Now, solve for \( x \):
\[ x = \frac{30}{1.05} \approx 28.57 \]
So, Emily can spend approximately $28.57 on the dress before tax.