Draw the following subsets of ℝ², indicating enough points to make the drawing clear. For some, you cannot draw them entirely. Make sure to draw enough so that anyone can understand.
a) The set of points satisfying y > x².
b) The set of points satisfying x² + y² < 9.
c) The set of points satisfying |x| + |y| ≤ 1.
d) The set of points satisfying y = 2x + 3.