18. Given two relations and R = {(x,b),(y,b),(y, a),(y,c)} with orderings 1,2,3;x,y;abc Answering the following questions. a. Find the matrix A, of relation R, relative to the orderings. R = {(1,x),(1,y),(2,x),(3,x)} b. Find the matrix A, of relation R, relative to the orderings. c. Find the matrix product 4,4. d. Use the result of part c to find the matrix of the relation R, DR. e. Use the result in part d to find the relation of R, DR, as a set of ordered pairs.