Recall Z={,2,1,0,1,2,} (the integers). Let Z+={1,2,3,} be the positive integers. Let 2Z be the even integers, 3Z be the multiples of 3 , and so on. a. Is Z+2Z ? Explain. b. Is 2ZZ+? Explain. c. Find 2Z3Z. Describe the set in words, and using set notation. d. Express {xZ:yZ(x=2yx=3y)} as a union or intersection of two sets already described in this