Solve for r: 5/3r + 4/3 = -8/9 answer you

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

Can you me find the slope! (30 points)

20 points + brainliest answer + my mom’s chocolate chip cookie ! subtract.