3.4 - 2.8d + 2.8d - 1.8

Which of the following is true for the relation f(x)=2x^2+1

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

Is the figure congruent? yes or no?