How would you describe the difference between the graphs of f (x)= 2x^2 and g(x)= -2x^2?

The difference between the graphs of f(x) and g(x) is the f(x) is an upright vertical parabola while g(x) is a vertical parabola that is reflected upon the x-axis.

Basically, g(x) is a reflection of f(x) over the x-axis.

the answer to the question is a  

it has the same slope and the same y-intercept.