y (1, 0) X (0, -1) a) Is this a function from a to y (eg y = f(x))? Why yes or why not, justify briefly? (2 pts) b) Which formula may have generated this curve ? (no need to justify, just identify the right answer) (3 pts) i) x2 + 2x - 1 - y =0 ii ) x2 - y - 1 =0 iii) y' + 2y - x +1=0 iv) None of the above