Sketch the graph of the function: (a). f(x, y)=x² +4y? (level curve = 0, 2, 4, (b). f(x, y)=x² + y² +3 (level curve = 3, 4, 5, (c). f(x, y) = 19-x-y? (level curve = 0, 1, 2, 3)

Let u = {q, r, s, t, u, v, w, x, y, z} a = {q, s, u, w, y} b = {q, s, y, z} c = {v, w, x, y, z}. list the elements in the set. a ∩ (b ∪ c)a) {q, s, w, y}b) {q, y, z}c) {q, s, u, w, y, z}d) {q, r, w, y, z}