There is a sales tax of $12 on an item that costs $126 before tax. a second item costs $105 before tax. what is the sales tax on the second item?
seriously me!

(c) the diagram shows the first three shapes of a matchsticks arrangement.first shape = 3second shape = 5third shape = 7given m represents the number of matchstick used to arrange the n'th shape.(i) write a formula to represent the relation between m and n. express m as the subjectof the formula.(ii) 19 matchsticks are used to make the p'th shape. find the value of p.