SOHCAHTOA can anyone help me with this

Which equation represents the partial sum of the geometric series?

Which compound inequality could be represented by the graph?

Jada has a meal in a restaurant she adds up the prices listed on the menu for everything they ordered and gets a subtotal of $42.00. when the check comes, it says they also need to pay $3.99 in sales tax. what percentage of the subtotal is the sales tax