For each of the following differential equations, state the order and determine whether it is linear or nonlinear. If the differential equation is linear, state whether it is homogeneous or nonhomogeneous

a. (1 − x)y'' − 3xy' + 7y = cos x
b. x 4y x 4 − 3 ( y x) 5 − y x − 6y = 0
c. y ′′′ − x 2y ′′ + y = tan y

(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.