Fill in each blank so that the resulting statement is true.

If the graph of a function f approaches b as x increases or decreases without bound, then the line y = b is a/an of the graph of f. The equation of such a line for the graph of y = x - 10/3x² + x + 1 is_________ . The equation of such a line for the graph of y = x² - 10/3x² + x + 1 is_________ . The equation of such a line for the graph of y = x² - 10/3x² + x + 1 is___________ .