Final answer:
The equation y = 2x² - 8x - 5 defines y as a function of x, as it assigns exactly one y value for each x value, resulting in a quadratic graph.
Step-by-step explanation:
The equation y = 2x² - 8x - 5 does indeed define y as a function of x. In this quadratic equation, for every value of x, there is one corresponding value of y. This is distinct from linear equations such as y = 6x + 8 and y + 7 = 3x, which are also functions because they too assign exactly one y value for every x value. However, the quadratic nature of y = 2x² - 8x - 5 means its graph will be a parabola, not a straight line as with linear equations. To graph a function and determine its nature, you can plot specific (x, y) data pairs based on the equation.