6. Glve an example showing that set subtraction is not associative. You may describe (e.g., list elements of) three sets and evaluate the left and right-hand sides to show that they are not equivalent; or you may demonstrate their inequality using Venn diagrams. We encourage you try both methods. to Define the sets X = (a, b, c} and Y = { 1, 2) Show the set X Y by listing the elements with set notation 7