graph of a negative parabola oriented about the y axis with y intercept at positive 6 : It's a function
graph of an absolute value function oriented about the y axis : it's a function called piecewise
graph of an ellipse with x intercepts negative 8 and positive 8 : it's not a function, since the vertical line intersects the ellipse in 2 different points
graph of a line with a positive slope and y intercept of negative 6: it's a linear function
