please help i do not understand how to do these

Problem 3: Let R1={(1,x),(1,y),(2,x),(3,x)};R2={(x,b),(y,b),(y,a),(y,c)}; ordering 1,2,3;x,y;a,b,c. Find a) The matrix A1 of the relation R1 (relative to the given ordering) b) The matrix A2 of the relation R2 (relative to the given ordering) c) The matrix product A1A2 d) Use the result of part (c) to find the matrix of relation R2R1 e) Use the result of part (d) to find the relation R2R1 (as a set of ordered pairs)