LAW OF SINES: I'm not sure how to solve this.

Which equation can be used to solve for the unknown number? seven less than a number is thirteen. n-7=13 7-n=13 n+7=13 n+13=7

(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.

Find two consexutive odd integers such that the sum of their square is 650