Math Evaluate each expression given that x=-21; y=-48; and z=72. a.) -z b.) -(-y) c.) x-y d.) -[y+(-x)] e.) x(y-z) Asked by Mharz2 10 years ago 6/8/2015 9:14 AM Last updated by anonymous 10 years ago 6/22/2015 9:49 AM