Ursula spent a total of $52.34 on two new outfits. She bought two shirt for $12.99, a pair of pants for $18.50, and a skirt. If the sales tax was 7.5%, what was the cost of the skirt?

Please solve and exlain. Thanks

let the cost of the skirt be x

1.075(12.99 + 18.5 + x) = 52.34
divide by 1.075
12.99 + 18.5 + x = 48.688
x = 17.20

The skirt cost $17.20