To find the unit price of gasoline, you need to divide the total cost by the number of gallons.
The total cost is $17.70 and the number of gallons is 5.
The unit price is calculated as follows:
\[ \text{Unit Price} = \frac{\text{Total Cost}}{\text{Number of Gallons}} = \frac{17.70}{5} = 3.54 \]
Therefore, the unit price is $3.54 per gallon.