A rectangular prism measuring 10 cm and 9 cm along the base and 2 cm tall

Does anyone know how to do geometryme with this problem

Which equation results from adding the equations in this system? x+6y=9 and -x+2y=-15

(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.